[PATCH] unify pfn_to_page: arm pfn_to_page

ARM can use generic funcs.
PFN_TO_NID, LOCAL_MAP_NR are defined by sub-archs.

Signed-off-by: KAMEZAWA Hirotuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>