usb: typec: mux: Allow the muxes to be named

The mux devices have been named by using the name of the
parent device as base until now, but if for example the
parent device has multiple muxes that will not work. This
makes it possible to supply the name for a mux during
registration.

Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Link: https://lore.kernel.org/r/20200302135353.56659-2-heikki.krogerus@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>