smb-lib: add support of DP/DM pulsing for QC2.0 adapter

This change will enable userspace to control adapter's output
voltage. Userspace can force adapter's output voltage to
5V/9V/12V.

Change-Id: I0c367e252c95b28c3b495578ce6552716e358c70
Signed-off-by: Ashay Jaiswal <ashayj@codeaurora.org>