MIPS: lantiq: handle vmmc memory reservation

The Lantiq SoCs have a 2nd mips core called "voice mips macro core (vmmc)"
which is used to run the voice firmware. This driver allows us to register
a chunk of memory that the voice driver can later use for the 2nd core.

Signed-off-by: John Crispin <blogic@openwrt.org>
Patchwork: http://patchwork.linux-mips.org/patch/8042/


Signed-off-by: Ralf Baechle <ralf@linux-mips.org>