power: smb1351: Enable HVDCP during charger driver probe

Since HVDCP is disabled by default, set the HVDCP_EN bit
during the smb1351-charger driver probe sequence.

Change-Id: I48ea1aa66fda83c33c52fdc3bad82f7bfa180c85
Signed-off-by: Devesh Jhunjhunwala <deveshj@codeaurora.org>