gpu: read grid and block sizes as soon as kernel object is created
gpu: read grid and block sizes as soon as kernel object is created

This makes sure the sizes are available inside create_kernel.

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

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