drm/msm: Fix legacy relocs path

[ Upstream commit c8d99bb ]

In moving code around, we ended up using the same pointer to
copy_from_user() the relocs tables as we used for the cmd table
entry, which is clearly not right.  This went unnoticed because
modern mesa on non-ancent kernels does not actually use relocs.
But this broke ancient mesa on modern kernels.

Reported-by: Emil Velikov <emil.velikov@collabora.com>
Fixes: 20224d7 ("drm/msm/submit: Move copy_from_user ahead of locking bos")
Signed-off-by: Rob Clark <robdclark@chromium.org>
Reviewed-by: Akhil P Oommen <akhilpo@codeaurora.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

drivers/gpu/drm/msm/msm_gem_submit.c

@@ -198,6 +198,8 @@ static int submit_lookup_cmds(struct msm_gem_submit *submit,
 		submit->cmd[i].idx  = submit_cmd.submit_idx;
 		submit->cmd[i].nr_relocs = submit_cmd.nr_relocs;
 
+		userptr = u64_to_user_ptr(submit_cmd.relocs);
+
 		sz = array_size(submit_cmd.nr_relocs,
 				sizeof(struct drm_msm_gem_submit_reloc));
 		/* check for overflow: */