Use MAP_FIXED in remapNewHeap

The heap address must not change when it is remapped

Change-Id: Ia44f178932e2afe8de3d4739e7085caae8568885
Signed-off-by: Pete Delaney <piet.delaney@imgtec.com>
Signed-off-by: Chris Dearman <chris.dearman@imgtec.com>
Clean-up some compiler warning messages.

Change-Id: I24522a57eaabedd4191856b80e5efe1b845be2fd