drm/amd/powerplay: fix locking in smu_feature_set_supported()

There is a typo so the code unlocks twice instead of taking the lock and
then releasing it.

Fixes: f14a323 ("drm/amd/powerplay: implement update enabled feature state to smc for smu11")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Huang Rui <ray.huang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/powerplay/amdgpu_smu.c

@@ -280,7 +280,7 @@ int smu_feature_set_supported(struct smu_context *smu, int feature_id,
 
 	WARN_ON(feature_id > feature->feature_num);
 
-	mutex_unlock(&feature->mutex);
+	mutex_lock(&feature->mutex);
 	if (enable)
 		test_and_set_bit(feature_id, feature->supported);
 	else