frontends/va: Fix *num_entrypoints check.

Fix defect reported by Coverity Scan.

Dereference before null check (REVERSE_INULL)
check_after_deref: Null-checking num_entrypoints suggests that it
may be null, but it has already been dereferenced on all paths
leading to the check.

Fixes: 5bcaa1b9e970 ("st/va: add encode entrypoint v2")
Signed-off-by: Vinson Lee <vlee@freedesktop.org>
Reviewed-by: Pierre-Eric Pelloux-Prayer <pierre-eric.pelloux-prayer@amd.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/7360>
(cherry picked from commit 7820c8c13ff3e9367b208f09059c940a1629f708)
2 files changed