power: smb1351-charger: Add SMB1351 charger driver

This driver supports SMB1351 switching mode based charger.
It allows charging control (enable/disable) and configuring
charge-current. It supports USB VBUS detection and notification
via the power_supply framework.

Change-Id: Idc4b4b8480aae6d02ac59a362c07c4dcdd59b5e7
Signed-off-by: Jie Cheng <rockiec@codeaurora.org>