gpu.c: extract_array_info: react more gracefully to unexpected events
gpu.c: extract_array_info: react more gracefully to unexpected events

In particular, tell the caller about the error rather than dumping core.

Signed-off-by: Sven Verdoolaege <e5350bbed4977f5eb8ae1dc6abd9ae59d21ace75@kotnet.org>

Meinersbur/ppcg,nicolasvasilache/ppcg,Meinersbur/ppcg,nicolasvasilache/ppcg