drm/radeon/dpm: make some functions static for sumo

Noticed by Rashika Kheria and cherry-picked from
her larger patch set.

Signed-off-by: Alex Deucher <[e-mail]>
Cc: Rashika Kheria <[e-mail]>

drivers/gpu/drm/radeon/sumo_dpm.c

···
 	SUMO_DTC_DFLT_14,
 };
 
-struct sumo_ps *sumo_get_ps(struct radeon_ps *rps)
+static struct sumo_ps *sumo_get_ps(struct radeon_ps *rps)
 {
 	struct sumo_ps *ps = rps->ps_priv;
 

drivers/gpu/drm/radeon/sumo_smc.c

···
 #define SUMO_SMU_SERVICE_ROUTINE_ALTVDDNB_NOTIFY  27
 #define SUMO_SMU_SERVICE_ROUTINE_GFX_SRV_ID_20  20
 
-struct sumo_ps *sumo_get_ps(struct radeon_ps *rps);
 struct sumo_power_info *sumo_get_pi(struct radeon_device *rdev);
 
 static void sumo_send_msg_to_smu(struct radeon_device *rdev, u32 id)