drm/etnaviv: fix submit flags getting overwritten by BO content

The addition of the flags member to etnaviv_gem_submit structure didn't
take into account that the last member of this structure is a variable
length array.
Signed-off-by: NLucas Stach <l.stach@pengutronix.de>

drivers/gpu/drm/etnaviv/etnaviv_gem.h

@@ -106,9 +106,10 @@ struct etnaviv_gem_submit {
 	struct etnaviv_gpu *gpu;
 	struct ww_acquire_ctx ticket;
 	struct dma_fence *fence;
+	u32 flags;
 	unsigned int nr_bos;
 	struct etnaviv_gem_submit_bo bos[0];
-	u32 flags;
+	/* No new members here, the previous one is variable-length! */
 };
 
 int etnaviv_gem_wait_bo(struct etnaviv_gpu *gpu, struct drm_gem_object *obj,