binary_rootfs stage: give custom MKSQUASHFS_OPTIONS precedence
courtesy of sed -i -r '/MKSQUASHFS_OPTIONS/ s/"(${.*}) ([^"]+)"/"\2 \1"/' scripts/build/binary_rootfs
courtesy of sed -i -r '/MKSQUASHFS_OPTIONS/ s/"(${.*}) ([^"]+)"/"\2 \1"/' scripts/build/binary_rootfs