udoo_neo: Call gpio_request()

Calling gpio_request() prior to its usage is now mandatory.

This fixes the following GPIO errors:
gpio@20a8000: set_dir_flags: error: gpio GPIO4_16 not reserved
gpio@20a8000: set_dir_flags: error: gpio GPIO4_13 not reserved
gpio@20a8000: set_dir_flags: error: gpio GPIO4_0 not reserved
gpio@20a8000: get_value: error: gpio GPIO4_13 not reserved
gpio@20a8000: get_value: error: gpio GPIO4_0 not reserved
gpio@20a0000: set_dir_flags: error: gpio GPIO2_1 not reserved
gpio@20a0000: set_value: error: gpio GPIO2_1 not reserved

Fixes: 191840ae ("ARM: imx: udoo_neo: Enable OF_CONTROL and DM gpio/pin control")
Signed-off-by: Peter Robinson <pbrobinson@gmail.com>
Reviewed-by: Fabio Estevam <festevam@gmail.com>