Resave guf_defconfig in the defconfig style

Original guf_imx_v6_v7_defconfig is currently saved in the .config style

Correct workflow is

make guf_imx_v6_v7_defconfig # Copy defconfig to working .config

make menuconfig # Make and save changes to .config

make savedefconfig # Save .config to defconfig format, creates defconfig file in workdir

cp defconfig arch/arm/configs/guf_imx_v6_v7_defconfig # Save over original defconfig