regulator: pv88080: Update regulator for PV88080 BB silicon support

Three files are modified, the driver, header file and the binding document.

Updates for the regulator source file include and .of_match_table entry
and node match checking in the probe() function for a compatible pv88080
silicon type. A new "HVBUCK" is added in source file and added
regsiter definition in header file for pv88080 bb silicion.
The binding documentation changes have been made to reflect these updates.

Signed-off-by: Eric Jeong <eric.jeong.opensource@diasemi.com>
Signed-off-by: Mark Brown <broonie@kernel.org>