[ARM] 4962/1: Introduce standard gpio interface for Scoop2.

This deprecates old set/reset_scoop_gpio interfacein favour of
support for generic gpio interface.

It requires gpiolib, so it depends on the previous patch
(gpiolib for SA-1100).

Signed-off-by: Dmitry Baryshkov <dbaryshkov@gmail.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>