ARM: tegra: harmony: add regulator supply name and its input supply

Name the regulator as per board schematics and adds its
supply name info in regulator data.
Add the always on fixed regulator to refer the battery supply.

Use this fixed regulator for input supply of some of PMIC
regulator

This patch was originally part of a 2-patch series. Patch 2 got applied
to the regulator tree as 7c7fac30

 "regulator: tps6586x: add support for
input supply" without this patch. This broke regulator support on
Harmony.

Signed-off-by: Laxman Dewangan <ldewangan@nvidia.com>
[swarren: added dependency info to commit description]
Signed-off-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>