regulator: pbias: Get rid of struct pbias_regulator_data

Only the desc field is really used, so use struct regulator_desc instead.
Then struct pbias_regulator_data can be removed.

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Link: https://lore.kernel.org/r/20191007114320.20977-1-axel.lin@ingics.com


Signed-off-by: Mark Brown <broonie@kernel.org>