microblaze: add support for handling PVR data

Add helper code for PVR (Processor Version Register) data handling. It
will be used by the UCLASS_CPU driver to populate cpuinfo fields at
runtime.

Signed-off-by: Ovidiu Panait <ovpanait@gmail.com>
Link: https://lore.kernel.org/r/20220531181435.3473549-13-ovpanait@gmail.com


Signed-off-by: Michal Simek <michal.simek@amd.com>