regulator: spm: check min/max voltages against HW configuration

Regulator HW has the programmable voltage upper and lower limit
registers and doesn't allow voltage set points outside the pre-
configured voltage limits. Add a check in driver that throws an
error if the SW specified voltage range is not within the pre-
configured limits in HW.

CRs-Fixed: 2044789
Change-Id: I3593ebf8e88824a0cfcb068686673a00051a11f0
Signed-off-by: Tirupathi Reddy <tirupath@codeaurora.org>