mxc: iomuxv1: Do not use gpio_request when setting the pin as GPIO

When setting the IOMUX of multiple pins via mxc_gpio_setup_multiple_pins, gpio_request
is called and this prevents subsequent calls of gpio_request done by drivers to succeed.

Remove gpio_request call from mxc_gpio_setup_multiple_pins function.

As gpio_request is removed from mxc_gpio_setup_multiple_pins, there is no need to have
mxc_gpio_release_multiple_pins anymore, so remove this function.

Tested on a mx27_3ds board and after applying this patch it is possible to define all the
IOMUX setup in a static array

Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>