Revert "mm/memblock: disable local irqs while late memblock changes"

This reverts commit a87081cf.
The reverted patch is part of the unused no-map-fixup feature which is
being removed.

Change-Id: I95c78f62e4c73a9a79a85afa30796c28d946b465
Signed-off-by: Vinayak Menon <vinmenon@codeaurora.org>