dt-bindings: usb: Add binding for fcs,fsa4480

The Fairchild/ON Semiconductor FSA4480 Analog Audio switch is used in
USB Type-C configurations for muxing analog audio onto the USB
connector, and as such used to control the SBU signals for altmodes such
as DisplayPort.

Add a binding for this hardware block.

Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/20220422222351.1297276-7-bjorn.andersson@linaro.org


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>