[ARM] 3847/2: Convert LOMOMO to use struct device for GPIOs

Convert LOMOMO to use struct device * for GPIOs instead of struct
locomo_dev. This enables access to the GPIOs from code which is not
a locomo device itself (such as audio). Access for gpio 31 is removed
for error handling (no such hardware exists).

Signed-off-by: Richard Purdie <rpurdie@rpsys.net>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>