usb: typec: mux: Allow the mux handles to be requested with fwnode

Introducing fwnode_typec_switch_get() and
fwnode_typec_mux_get() functions that work just like
typec_switch_get() and typec_mux_get() but they take struct
fwnode_handle as the first parameter instead of struct
device.

Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Link: https://lore.kernel.org/r/20200302135353.56659-4-heikki.krogerus@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>