drm/amdgpu: use adev_to_drm for consistency

Keep code consistency when accessing drm_device from amdgpu driver.
Signed-off-by: Guchun Chen <guchun.chen@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/amdgpu/vcn_v4_0.c

@@ -154,7 +154,7 @@ static int vcn_v4_0_sw_fini(void *handle)
 	struct amdgpu_device *adev = (struct amdgpu_device *)handle;
 	int i, r, idx;
 
-	if (drm_dev_enter(&adev->ddev, &idx)) {
+	if (drm_dev_enter(adev_to_drm(adev), &idx)) {
 		for (i = 0; i < adev->vcn.num_vcn_inst; i++) {
 			volatile struct amdgpu_vcn4_fw_shared *fw_shared;