MIPS: c-r4k: Split r4k_flush_kernel_vmap_range()

Split the operation of r4k_flush_kernel_vmap_range() into separate
SMP callbacks for the indexed cache flush and hit cache flush cases,
since the logic to determine which to use can be determined by the
initiating CPU prior to doing any SMP calls.

This will help when we change r4k_on_each_cpu() to distinguish indexed
and hit cache ops in a later patch, preventing globalized hit cache ops
being performed redundantly on multiple CPUs.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: Leonid Yegoshin <leonid.yegoshin@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/13806/


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