MIPS: Lantiq: Add mips_machine support

This patch adds support for Gabor's mips_machine patch.

Signed-off-by: John Crispin <blogic@openwrt.org>
Signed-off-by: Ralph Hempel <ralph.hempel@lantiq.com>
Cc: Gabor Juhos <juhosg@openwrt.org>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/2251/
Patchwork: https://patchwork.linux-mips.org/patch/2358/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>