drm/msm/submit: fix overflow check on 64-bit architectures

The overflow check does causes a warning from clang-14 when 'sz' is a type
that is smaller than size_t:

drivers/gpu/drm/msm/msm_gem_submit.c:217:10: error: result of comparison of constant 18446744073709551615 with expression of type 'unsigned int' is always false [-Werror,-Wtautological-constant-out-of-range-compare]
                if (sz == SIZE_MAX) {

Change the type accordingly.

Fixes: 20224d7 ("drm/msm/submit: Move copy_from_user ahead of locking bos")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Link: https://lore.kernel.org/r/20210927113632.3849987-1-arnd@kernel.org
Signed-off-by: Rob Clark <robdclark@chromium.org>

Author: arndb

drivers/gpu/drm/msm/msm_gem_submit.c

@@ -171,7 +171,8 @@ static int submit_lookup_objects(struct msm_gem_submit *submit,
 static int submit_lookup_cmds(struct msm_gem_submit *submit,
 		struct drm_msm_gem_submit *args, struct drm_file *file)
 {
-	unsigned i, sz;
+	unsigned i;
+	size_t sz;
 	int ret = 0;
 
 	for (i = 0; i < args->nr_cmds; i++) {