gpio: driver for PrimeCell PL061 GPIO controller

This is a driver for the ARM PrimeCell PL061 GPIO AMBA peripheral.  The
driver is implemented using the gpiolib framework.

This driver also includes support for the use of the PL061 as an interrupt
controller (secondary).

Signed-off-by: Baruch Siach <baruch@tkos.co.il>
Cc: David Brownell <david-b@pacbell.net>
Acked-by: Russell King <rmk@arm.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>