Patch from Sascha Hauer

Current implementation of imx_gpio_mode does not allow to
configure all alternate routing possibilities of the i.MX. With
this patch every bit in the gpio setup registers has a
corresponding bit in the gpio_mode parameter, so every routing
should be possible now.
Signed-off-by: NSascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>