ARM: 8787/1: wire up io_pgetevents syscall

Wire up the new io_pgetevents syscall for ARM.

Signed-off-by: Stefan Agner <stefan@agner.ch>
Acked-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>