regulator: Fairchild fan53555 support

This driver supports Fairchild FAN53555 Digitally Programmable
TinyBuck Regulator. The FAN53555 is a step-down switching voltage
regulator that delivers a digitally programmable output from an
input voltage supply of 2.5V to 5.5V. The output voltage is
programmed through an I2C interface.

Change-Id: I9b79deee1a3f10fe58598efa68ace7f9882bf53d
Signed-off-by: Yunfan Zhang <yfzhang@marvell.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Git-commit: 49d8c59927e7887ea168a040e41c22937e10c30b
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
[keliu@codeaurora.org: resolve merge conflicts]
Signed-off-by: Ke Liu <keliu@codeaurora.org>
4 files changed