fix handling of --no-private-memory and --no-shared-memory
fix handling of --no-private-memory and --no-shared-memory

Support for these flags was broken in 5da0148 (gpu.c: compute private tile
during array reference grouping, Sat Dec 15 15:46:13 2012 +0100).
In particular, since then the --no-private-memory and --no-shared-memory
options were only respected if both of them were specified.

Also handle the options individually.

Reported-by: Tobias Grosser <059b8b880f8441509ec8a65b50b4c6ae74ebea76@grosser.es>
Signed-off-by: Sven Verdoolaege <e5350bbed4977f5eb8ae1dc6abd9ae59d21ace75@kotnet.org>

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