power: smb349: add support for smb349 charger chip

The SMB349 charger chip allows charge batteries
with a higher current. Add this driver to be able to
control charging from kernel space and deliver charging
information to userspace.

Also add debugfs entries to show current register
settings of SMB349 charger.

Change-Id: Ic88b539304539a49ebe69517d13045cbb18091bf
Signed-off-by: David Keitel <dkeitel@codeaurora.org>