mm: remove CONFIG_OUT_OF_LINE_PFN_TO_PAGE

No architectures use CONFIG_OUT_OF_LINE_PFN_TO_PAGE - it can be removed.

Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>