MIPS: c-r4k: Treat physically indexed dcaches as not aliasing

Physically indexed caches cannot suffer from virtual aliasing, so clear
the MIPS_CACHE_ALIASES bit in order to ensure we don't do extra work
avoiding aliasing that cannot happen.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/14017/


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