epoll cleanups: epoll remove static pre-declarations and akpm-ize the code

Re-arrange epoll code to avoid static functions pre-declarations, and apply
akpm-filter on it.
Signed-off-by: NDavide Libenzi <davidel@xmailserver.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>