usb: typec: tcpci: Add set_vbus tcpci callback

set_vbus callback allows TCPC which are TCPCI based, however,
does not support turning on sink and source mode through
Command.SinkVbus and Command.SourceVbusDefaultVoltage.

Signed-off-by: Badhri Jagan Sridharan <badhri@google.com>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Link: https://lore.kernel.org/r/20201008061556.1402293-3-badhri@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>