staging: typec: tcpci: enable vbus detection

TCPCI implementation may need SW to enable VBUS detection to generate
power status events.

Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Li Jun <jun.li@nxp.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>