[ARM] arm's arch_local_page_offset() fix against 2.6.17-rc1

This patch fixes arch_local_page_offset(pfn,nid) in arm.
This new one (added by unify_pfn_to_page patches) is obviously buggy.

This macro calculate page offset in a node.

Note: about LOCAL_MAP_NR()
comment in arm's sub-archs says...

 /*
  * Given a kaddr, LOCAL_MAP_NR finds the owning node of the memory
  * and returns the index corresponding to the appropriate page in the
  * node's mem_map.
  */

but LOCAL_MAP_NR() is designed to be able to take both paddr and kaddr.
In this case, paddr is better.

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitu.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>