power: Add support for TPS65090 PMU chip.

This adds driver support for the TPS65090 PMU. Support includes
hooking into the pmic infrastructure  so that the pmic commands
can be used on the console. The TPS65090 supports the following
functionality:

- fet enable/disable/querying
- getting and setting of charge state

Even though it is connected to the pmic infrastructure it does
not hook into the pmic charging charging infrastructure.

The device tree binding is from Linux, but only a small subset of
functionality is supported.

Signed-off-by: Tom Wai-Hong Tam <waihong@chromium.org>
Signed-off-by: Hatim Ali <hatim.rv@samsung.com>
Signed-off-by: Katie Roberts-Hoffman <katierh@chromium.org>
Signed-off-by: Rong Chang <rongchang@chromium.org>
Signed-off-by: Sean Paul <seanpaul@chromium.org>
Signed-off-by: Vincent Palatin <vpalatin@chromium.org>
Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Signed-off-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Minkyu Kang <mk7.kang@samsung.com>