As per example from the other ARM boards, push the LPC32XX
GPIO driver down to the GPIO subsystem so it can be consolidated.

Cc: Wolfram Sang <w.sang@pengutronix.de>
Cc: Barry Song <bs14@csr.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>