[PATCH] remove direct ref to contig_page_data for x86-64

This patch pulls out all remaining direct references to contig_page_data
from arch/x86-64, thus saving an ifdef in one case.

Signed-off-by: Matt Tolentino <matthew.e.tolentino@intel.com>
Signed-off-by: Dave Hansen <haveblue@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>