arm: ls102xa: Add dummy gpio.h to enable CONFIG_OF_CONTROL

arm: ls102xa: Add dummy gpio.h to enable CONFIG_OF_CONTROL

If CONFIG_OF_CONTROL is enabled, lib/fdtdec.c is compiled.
It includes <asm/gpio.h> and then <asm/gpio.h> includes
<asm/arch/gpio.h>.  As a result, all the SoCs that enable
CONFIG_OF_CONTROL must have <asm/arch/gpio.h> even if they
do not support GPIO.

The right fix would be to split the lib/fdtdec.c to remove
dependency on GPIO.This commit adds a dummy <asm/arch/gpio.h>
to support OF_CONTROL for LS102x platform. This dummy header
will be removed after FDT-GPIO stuff is fixed correctly.

Signed-off-by: Ruchika Gupta <ruchika.gupta@freescale.com>
Reviewed-by: York Sun <yorksun@freescale.com>