drm/msm: move fence allocation out of msm_gpu_submit()

Prep work for next patch.

Signed-off-by: Rob Clark <robdclark@gmail.com>
diff --git a/drivers/gpu/drm/msm/msm_gem_submit.c b/drivers/gpu/drm/msm/msm_gem_submit.c
index 3a4a8dd..65284fe 100644
--- a/drivers/gpu/drm/msm/msm_gem_submit.c
+++ b/drivers/gpu/drm/msm/msm_gem_submit.c
@@ -488,7 +488,14 @@
 
 	submit->nr_cmds = i;
 
-	ret = msm_gpu_submit(gpu, submit, ctx);
+	submit->fence = msm_fence_alloc(gpu->fctx);
+	if (IS_ERR(submit->fence)) {
+		ret = PTR_ERR(submit->fence);
+		submit->fence = NULL;
+		goto out;
+	}
+
+	msm_gpu_submit(gpu, submit, ctx);
 
 	args->fence = submit->fence->seqno;