To align with other i.mx6 platforms, update config file to remove some unnecessary settings. Also enable the GPIO command.
Signed-off-by: Ye Li
CONFIG_SYS_EXTRA_OPTIONS="IMX_CONFIG=board/freescale/mx6ull_ddr3_arm2/imximage.cfg" CONFIG_ARM=y CONFIG_ARCH_MX6=y CONFIG_TARGET_MX6ULL_DDR3_ARM2=y CONFIG_CMD_GPIO=y