etnaviv: Fix memory leak on error path.

etnaviv: Fix memory leak on error path.

Fix warning reported by Coverity Scan.

Resource leak (RESOURCE_LEAK)
leaked_storage: Variable pq going out of scope leaks the storage it
points to.

Suggested-by: Christian Gmeiner <christian.gmeiner@gmail.com>
Fixes: eed5a009897a ("etnaviv: convert perfmon queries to acc queries")
Signed-off-by: Vinson Lee <vlee@freedesktop.org>
Reviewed-by: Christian Gmeiner <christian.gmeiner@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/5220>