gpu.c: remove_local_accesses_group: pass in prefix schedule
gpu.c: remove_local_accesses_group: pass in prefix schedule

The caller extracts the very same prefix schedule relation as
the one that is extracted inside of remove_local_accesses_group.
Just pass in the prefix schedule relation instead of extracting
it twice.

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

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