drm/amdgpu/virtual_dce: move define into source file

It's not used outside the file.

Reviewed-by: Christian König <[e-mail]>
Signed-off-by: Alex Deucher <[e-mail]>

drivers/gpu/drm/amd/amdgpu/dce_virtual.c

···
 #include "dce_v11_0.h"
 #include "dce_virtual.h"
 
+#define DCE_VIRTUAL_VBLANK_PERIOD 16666666
+
+
 static void dce_virtual_set_display_funcs(struct amdgpu_device *adev);
 static void dce_virtual_set_irq_funcs(struct amdgpu_device *adev);
 static int dce_virtual_connector_encoder_init(struct amdgpu_device *adev,

drivers/gpu/drm/amd/amdgpu/dce_virtual.h

···
 #define __DCE_VIRTUAL_H__
 
 extern const struct amd_ip_funcs dce_virtual_ip_funcs;
-#define DCE_VIRTUAL_VBLANK_PERIOD 16666666
 
 #endif