drm/amd/powerplay: Remove unneeded variable 'result' in vega12_hwmgr.c

Fixes coccicheck warning:

drivers/gpu/drm/amd/powerplay/hwmgr/vega12_hwmgr.c:502:5-11: Unneeded variable: "result". Return "0" on line 515
Reported-by: NHulk Robot <hulkci@huawei.com>
Signed-off-by: Nzhengbin <zhengbin13@huawei.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/powerplay/hwmgr/vega12_hwmgr.c

@@ -499,8 +499,6 @@ static int vega12_get_number_of_dpm_level(struct pp_hwmgr *hwmgr,
 static int vega12_get_dpm_frequency_by_index(struct pp_hwmgr *hwmgr,
 		PPCLK_e clkID, uint32_t index, uint32_t *clock)
 {
-	int result = 0;
-
 	/*
 	 *SMU expects the Clock ID to be in the top 16 bits.
 	 *Lower 16 bits specify the level
@@ -512,7 +510,7 @@ static int vega12_get_dpm_frequency_by_index(struct pp_hwmgr *hwmgr,
 
 	*clock = smum_get_argument(hwmgr);
 
-	return result;
+	return 0;
 }
 
 static int vega12_setup_single_dpm_table(struct pp_hwmgr *hwmgr,