Increase chunk alignment from 256 to 512.
Restores performance in some workloads with pool enabled but lowers maximum
possible number of buffers in pool from 256 to 128.
MemObj size will keep the value passed to clCreateBuffer ie. will not be
aligned up by chunk alignment.
CL_MEM_SIZE will now return same value as with pool disabled.
Related-To: NEO-7332
Signed-off-by: Dominik Dabek <dominik.dabek@intel.com>