x86, mm: Move init_gbpages() out of setup.c

Put it in mm/init.c, and call it from probe_page_mask().
init_mem_mapping is calling probe_page_mask at first.
So calling sequence is not changed.

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Link: http://lkml.kernel.org/r/1353123563-3103-32-git-send-email-yinghai@kernel.org


Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>