Reference manuals of OMAP5x and DRA7x have been updated to reflect
the PBIAS regulator max-voltage as 3.3V instead of 3.0V, while OMAP3x
and OMAP4x are still quoting 3.0V. So, as of now, the pbias driver
needs to support both 3.0V and 3.3V IO voltage based on the max-voltage
supported by the PBIAS regulator.

Document reference:
SWPU249AF - OMAP543x Technical reference manual - August 2016
SPRUI30C – DRA75x, DRA74x Technical reference manual November 2016

Tested on:
DRA75x PG 2.0 REV H EVM
Signed-off-by: Ravikumar Kattekola <rk@ti.com>
Signed-off-by: Sekhar Nori <nsekhar@ti.com>
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
Signed-off-by: Mark Brown <broonie@kernel.org>