drm/mgag200: Fix logic in mgag200_bo_pin() (v2)

Add missing 'return 0;'.

v2: Simplified patch as suggested by Dave Airlie <airlied@redhat.com>
Signed-off-by: Egbert Eich <eich@suse.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

drivers/gpu/drm/mgag200/mgag200_ttm.c

@@ -353,6 +353,7 @@ int mgag200_bo_pin(struct mgag200_bo *bo, u32 pl_flag, u64 *gpu_addr)
 		bo->pin_count++;
 		if (gpu_addr)
 			*gpu_addr = mgag200_bo_gpu_offset(bo);
+		return 0;
 	}
 
 	mgag200_ttm_placement(bo, pl_flag);