MIPS: mm: Remove redundant get_new_mmu_context() cpu argument

get_new_mmu_context() accepts a cpu argument, but implicitly assumes
that this is always equal to smp_processor_id() by operating on the
local CPU's TLB & icache.

Remove the cpu argument and have get_new_mmu_context() call
smp_processor_id() instead.

Signed-off-by: Paul Burton <paul.burton@mips.com>
Cc: linux-mips@vger.kernel.org