drm/amd/display: Turn functions into static

Silence [-Wmissing-prototypes] sparse warnings from the display folder
such as:

../drivers/gpu/drm/amd/amdgpu/../display/dc/clk_mgr/dcn315/dcn315_smu.c:126:5: warning: no previous prototype for ‘dcn315_smu_send_msg_with_param’ [-Wmissing-prototypes]
  126 | int dcn315_smu_send_msg_with_param(
      |     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

v2: drop unused function dcn315_smu_set_voltage_via_phyclk() to avoid
    adding a warning (Alex)

Cc: Qingqing Zhuo (Lillian) <qingqing.zhuo@amd.com>
Reviewed-by: NHarry Wentland <harry.wentland@amd.com>
Reported-by: Nkernel test robot <lkp@intel.com>
Signed-off-by: NMagali Lemes <magalilemes00@gmail.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/dc/clk_mgr/dcn315/dcn315_clk_mgr.c

@@ -430,7 +430,7 @@ static unsigned int find_clk_for_voltage(
 	return 0;
 }
 
-void dcn315_clk_mgr_helper_populate_bw_params(
+static void dcn315_clk_mgr_helper_populate_bw_params(
 		struct clk_mgr_internal *clk_mgr,
 		struct integrated_info *bios_info,
 		const DpmClocks_315_t *clock_table)

drivers/gpu/drm/amd/display/dc/clk_mgr/dcn315/dcn315_smu.c

@@ -123,7 +123,7 @@ static uint32_t dcn315_smu_wait_for_response(struct clk_mgr_internal *clk_mgr, u
 	return res_val;
 }
 
-int dcn315_smu_send_msg_with_param(
+static int dcn315_smu_send_msg_with_param(
 		struct clk_mgr_internal *clk_mgr,
 		unsigned int msg_id, unsigned int param)
 {
@@ -181,21 +181,6 @@ int dcn315_smu_set_dispclk(struct clk_mgr_internal *clk_mgr, int requested_dispc
 
 	return actual_dispclk_set_mhz * 1000;
 }
-int dcn315_smu_set_voltage_via_phyclk(struct clk_mgr_internal *clk_mgr, int requested_phyclk_khz)
-{
-	int actual_phypclk_set_mhz = -1;
-
-	if (!clk_mgr->smu_present && requested_phyclk_khz)
-		return requested_phyclk_khz;
-
-	/*  Unit of SMU msg parameter is Mhz */
-	actual_phypclk_set_mhz = dcn315_smu_send_msg_with_param(
-			clk_mgr,
-			VBIOSSMC_MSG_SetPhyclkVoltageByFreq,
-			khz_to_mhz_ceil(requested_phyclk_khz));
-
-	return actual_phypclk_set_mhz * 1000;
-}
 
 int dcn315_smu_set_hard_min_dcfclk(struct clk_mgr_internal *clk_mgr, int requested_dcfclk_khz)
 {

drivers/gpu/drm/amd/display/dc/irq/dcn315/irq_service_dcn315.c

@@ -42,7 +42,7 @@
 #define DCN_BASE__INST0_SEG4                       0x02403C00
 #define DCN_BASE__INST0_SEG5                       0
 
-enum dc_irq_source to_dal_irq_source_dcn315(
+static enum dc_irq_source to_dal_irq_source_dcn315(
 		struct irq_service *irq_service,
 		uint32_t src_id,
 		uint32_t ext_id)