Invalidate requests align to system cache line size. This causes
problems if the GPU cache hierarchy's cache line size is different than
the system as the unlaigned requests never return, leading to deadlock
on deferred dispatch.
This commit uses the cache line size from the GPU memory manager and
makes the cache line size there non-optional.
Tested with multiple RubySystems where CPU side was 64B and GPU side was
128B cache lines.
24504c9a3e