drm/radeon/radeon_audio: Move 'r600_*' prototypes into shared header

Fixes the following W=1 kernel build warning(s):

drivers/gpu/drm/radeon/r600_hdmi.c:177:6: warning: no previous prototype for ‘r600_hdmi_update_acr’ [-Wmissing-prototypes]
177 | void r600_hdmi_update_acr(struct drm_encoder *encoder, long offset,
| ^~~~~~~~~~~~~~~~~~~~
drivers/gpu/drm/radeon/r600_hdmi.c:217:6: warning: no previous prototype for ‘r600_set_avi_packet’ [-Wmissing-prototypes]
217 | void r600_set_avi_packet(struct radeon_device *rdev, u32 offset,
| ^~~~~~~~~~~~~~~~~~~
drivers/gpu/drm/radeon/r600_hdmi.c:314:6: warning: no previous prototype for ‘r600_hdmi_audio_set_dto’ [-Wmissing-prototypes]
314 | void r600_hdmi_audio_set_dto(struct radeon_device *rdev,
| ^~~~~~~~~~~~~~~~~~~~~~~
drivers/gpu/drm/radeon/r600_hdmi.c:340:6: warning: no previous prototype for ‘r600_set_vbi_packet’ [-Wmissing-prototypes]
340 | void r600_set_vbi_packet(struct drm_encoder *encoder, u32 offset)
| ^~~~~~~~~~~~~~~~~~~
drivers/gpu/drm/radeon/r600_hdmi.c:351:6: warning: no previous prototype for ‘r600_set_audio_packet’ [-Wmissing-prototypes]
351 | void r600_set_audio_packet(struct drm_encoder *encoder, u32 offset)
| ^~~~~~~~~~~~~~~~~~~~~
drivers/gpu/drm/radeon/r600_hdmi.c:393:6: warning: no previous prototype for ‘r600_set_mute’ [-Wmissing-prototypes]
393 | void r600_set_mute(struct drm_encoder *encoder, u32 offset, bool mute)
| ^~~~~~~~~~~~~
drivers/gpu/drm/radeon/r600_hdmi.c:469:6: warning: no previous prototype for ‘r600_hdmi_enable’ [-Wmissing-prototypes]
469 | void r600_hdmi_enable(struct drm_encoder *encoder, bool enable)
| ^~~~~~~~~~~~~~~~

Cc: Alex Deucher <[e-mail]>
Cc: "Christian König" <[e-mail]>
Cc: David Airlie <[e-mail]>
Cc: Daniel Vetter <[e-mail]>
Cc: [e-mail]
Cc: [e-mail]
Signed-off-by: Lee Jones <[e-mail]>
Signed-off-by: Alex Deucher <[e-mail]>

drivers/gpu/drm/radeon/r600.h

···
 
 struct radeon_bo_list;
 struct radeon_cs_parser;
+struct r600_audio_pin;
+struct radeon_crtc;
 struct radeon_device;
+struct radeon_hdmi_acr;
 
 u32 r600_gpu_check_soft_reset(struct radeon_device *rdev);
 int r600_ih_ring_alloc(struct radeon_device *rdev);
 void r600_ih_ring_fini(struct radeon_device *rdev);
 
+void r600_audio_enable(struct radeon_device *rdev, struct r600_audio_pin *pin,
+		       u8 enable_mask);
+void r600_set_audio_packet(struct drm_encoder *encoder, u32 offset);
+void r600_set_mute(struct drm_encoder *encoder, u32 offset, bool mute);
+void r600_hdmi_audio_set_dto(struct radeon_device *rdev,
+			     struct radeon_crtc *crtc, unsigned int clock);
+void r600_set_avi_packet(struct radeon_device *rdev, u32 offset,
+			 unsigned char *buffer, size_t size);
+void r600_hdmi_update_acr(struct drm_encoder *encoder, long offset,
+			  const struct radeon_hdmi_acr *acr);
+void r600_set_vbi_packet(struct drm_encoder *encoder, u32 offset);
+void r600_hdmi_enable(struct drm_encoder *encoder, bool enable);
+
 int r600_dma_cs_next_reloc(struct radeon_cs_parser *p,
 			   struct radeon_bo_list **cs_reloc);
+
 #endif				/* __R600_H__ */

drivers/gpu/drm/radeon/r600_hdmi.c

···
 #include "radeon.h"
 #include "radeon_asic.h"
 #include "radeon_audio.h"
+#include "r600.h"
 #include "r600d.h"
 #include "atom.h"
 

drivers/gpu/drm/radeon/radeon_audio.c

···
 #include "evergreen_hdmi.h"
 #include "radeon.h"
 #include "atom.h"
+#include "r600.h"
 #include "radeon_audio.h"
 
-void r600_audio_enable(struct radeon_device *rdev, struct r600_audio_pin *pin,
-		u8 enable_mask);
 void dce6_audio_enable(struct radeon_device *rdev, struct r600_audio_pin *pin,
 		u8 enable_mask);
 struct r600_audio_pin* r600_audio_get_pin(struct radeon_device *rdev);
 struct r600_audio_pin* dce6_audio_get_pin(struct radeon_device *rdev);
-void r600_hdmi_audio_set_dto(struct radeon_device *rdev,
-	struct radeon_crtc *crtc, unsigned int clock);
-void r600_set_avi_packet(struct radeon_device *rdev, u32 offset,
-	unsigned char *buffer, size_t size);
-void r600_hdmi_update_acr(struct drm_encoder *encoder, long offset,
-	const struct radeon_hdmi_acr *acr);
-void r600_set_vbi_packet(struct drm_encoder *encoder, u32 offset);
-void r600_set_audio_packet(struct drm_encoder *encoder, u32 offset);
-void r600_set_mute(struct drm_encoder *encoder, u32 offset, bool mute);
 static void radeon_audio_hdmi_mode_set(struct drm_encoder *encoder,
 	struct drm_display_mode *mode);
 static void radeon_audio_dp_mode_set(struct drm_encoder *encoder,
 	struct drm_display_mode *mode);
-void r600_hdmi_enable(struct drm_encoder *encoder, bool enable);
 
 static const u32 pin_offsets[7] =
 {