power: smb349-charger: Add regulator for OTG support

SMB349 charger can operate in two modes one for normal charging and
in a 5V boost mode to support USB OTG.
Add regulator to control the OTG functionality of SMB charger.

Change-Id: I91dcc1cd091a884ada4077ea88ebf6ffa2beefc1
Signed-off-by: Ashay Jaiswal <ashayj@codeaurora.org>