power: smb-lib: Add support for SW based OV detection

Add support for software based USBIN OV detection, once
OV condition is detected, software will force USBIN to 5V
and continue charging with 5V.

Change-Id: Ie8f00f69db4ac6330d9da82b3455e4efab43861a
Signed-off-by: Umang Agrawal <uagrawal@codeaurora.org>