[ARM] 5564/1: at91: add gpio button and leds support for at91sam9rlek

This adds input keyboard gpio support on at91sam9rlek board. It adds button 1
and 2 (left and right click).
It also adds gpio leds ds1, ds2 and ds3.

Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Acked-by: Andrew Victor <linux@maxim.org.za>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>