drm/amdgpu: make smu_v13_0_7_check_fw_status() static

It's not used outside of the this file.
Reviewed-by: Kenneth Feng <kenneth.feng@amd.com>
Reviewed-by: Guchun Chen <guchun.chen@amd.com>
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/pm/swsmu/smu13/smu_v13_0_7_ppt.c

@@ -292,7 +292,8 @@ static int smu_v13_0_7_store_powerplay_table(struct smu_context *smu)
 	return 0;
 }
 
-int smu_v13_0_7_check_fw_status(struct smu_context *smu) {
+static int smu_v13_0_7_check_fw_status(struct smu_context *smu)
+{
 	struct amdgpu_device *adev = smu->adev;
 	uint32_t mp1_fw_flags;