power: smb5: Allow limiting VBUS using power supply property

Add support to dynamically change the maximum USB input voltage that
can be attained using power supply property voltage_max_limit.

Change-Id: I7aec5dde4c69740ac0f2477c6c7aa8609aa2ac78
Signed-off-by: Umang Agrawal <uagrawal@codeaurora.org>
Signed-off-by: Subbaraman Narayanamurthy <subbaram@codeaurora.org>