usb: typec: intel_pmc_mux: Add support for USB4

usb: typec: intel_pmc_mux: Add support for USB4

The PMC mux-agent can be used also to enter USB4 mode. The
mux-agent does not have USB4 specific message, but it can be
put into the TBT3 alternate mode also with USB4. That is OK
because the controller is in any case the same with TBT3 and
USB4.

Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Link: https://lore.kernel.org/r/20200701115618.22482-5-heikki.krogerus@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>