drm/amd: Use `amdgpu_ucode_release` helper for powerplay

The `amdgpu_ucode_release` helper is replacing all calls to
release_firmware.
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Reviewed-by: Lijo Lazar <lijo.lazar@amd.com>
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/pm/powerplay/amd_powerplay.c

@@ -111,8 +111,7 @@ static int pp_sw_fini(void *handle)
 
 	hwmgr_sw_fini(hwmgr);
 
-	release_firmware(adev->pm.fw);
-	adev->pm.fw = NULL;
+	amdgpu_ucode_release(&adev->pm.fw);
 
 	return 0;
 }