power: qpnp-smbcharger: add the qpnp smbcharger driver

The qpnp smbcharger is a dual path switch mode battery charger
peripheral with a max rating of 3Amps of current. Add a driver
to support this charging peripheral.

Change-Id: I9bfa2c2a5462570380b989b5f63f23c44146c82d
Signed-off-by: Xiaozhe Shi <xiaozhes@codeaurora.org>