ARM: 7902/1: sa1100: h3xxx: move serial port GPIO handling to common place

Both h3100 and h3600 request UART gpios during init_machine time. As
sa1100 gpio driver is going to become proper machine driver, move gpio
handling to UART port functions. Request all gpios using gpio_request
array once and then guard them from rerequesting with bool variable.

Signed-off-by: Dmitry Eremin-Solenikov <dbaryshkov@gmail.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>