[PATCH] convert hugetlbfs_counter to atomic

Implementation of hugetlbfs_counter() is functionally equivalent to
atomic_inc_return().  Use the simpler atomic form.

Signed-off-by: Ken Chen <kenneth.w.chen@intel.com>
Cc: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>