power: pmic: add the base TPS80031 PMIC support

Add support to bind the regulators/child nodes with the pmic.
Also adds the pmic i2c based read/write functions to access pmic
registers.

Signed-off-by: Svyatoslav Ryhel <clamor95@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
5 files changed