ENGR00269945: ARM: imx: add an ARMv7 only defconfig
To utilize ARMv7 optimization, let's maintain an ARMv7 only defconfig
imx_v7_defconfig. It's generated as below.
* make ARCH=arm imx_v6_v7_defconfig
* make ARCH=arm menuconfig
* System Type ---> Multiple platform selection ---> Deselect ARMv6
based platforms (ARM11)
* make ARCH=arm savedefconfig
* cp defconfig arch/arm/configs/imx_v7_defconfig