dt-bindings: connector: usb: add altmodes description

Add description of the USB-C AltModes supported on the particular USB-C
connector. This is required for devices like Qualcomm Robotics RB5,
which have no other way to express alternative modes supported by the
hardware platform.

Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Link: https://lore.kernel.org/r/20231204020303.2287338-2-dmitry.baryshkov@linaro.org


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