MIPS: CM: Provide a function to map from CPU to VP ID.

MIPS: CM: Provide a function to map from CPU to VP ID.

The VP ID of a given CPU may not match up with the CPU number used by
Linux. For example, if the width of the VP part of the VP ID is wider
than log2(number of VPs per core) and the system has multiple cores then
this will be the case. Alternatively, if a pre-r6 system implements the
MT ASE with multiple VPEs per core and Linux is built without support
for the MT ASE then the numbers won't match up either. Provide a
function to convert from CPU number to VP ID.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Cc: James Hogan <james.hogan@imgtec.com>
Cc: Markos Chandras <markos.chandras@imgtec.com>
Patchwork: https://patchwork.linux-mips.org/patch/11211/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>