i2c: Add TPS6586X driver

This power management chip supports battery charging and a large number
of power supplies. This initial driver only provides the ability to adjust
the two synchronous buck converters SM0 and SM1 in a stepwise manner.

Signed-off-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Tom Warren <twarren@nvidia.com>
3 files changed