dt-bindings: phy: qcom,sc7180-qmp-usb3-dp-phy: Add orientation-switch as optional

dt-bindings: phy: qcom,sc7180-qmp-usb3-dp-phy: Add orientation-switch as optional

orientation-switch it the standard declaration to inform the Type-C mux
layer that a remote-endpoint is capable of processing orientation change
messages.

Add as an optional since not all versions of the dp-phy currently support
the orientation-switch.

Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>
Link: https://lore.kernel.org/r/20230515133643.3621656-4-bryan.odonoghue@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>