MLK-14400-1 defconfig: fix warning in imx_v7_defconfig

MLK-14400-1 defconfig: fix warning in imx_v7_defconfig

when use imx_v7_defconfig, there are following warning:

arch/arm/configs/imx_v7_defconfig:172:warning: override: reassigning to symbol TOUCHSCREEN_IMX6UL_TSC
arch/arm/configs/imx_v7_defconfig:392:warning: override: reassigning to symbol ION
arch/arm/configs/imx_v7_defconfig:393:warning: override: reassigning to symbol ION_MXC

This patch use command 'make savedefconfig' to produce the defconfig
and replace the imx_v7_defconfig.

Signed-off-by: Haibo Chen <haibo.chen@nxp.com>