arm64: dts: qcom: sm8350-microsoft-surface: fix USB dual-role mode property

The "dr_mode" is a property of USB DWC3 node, not the Qualcomm wrapper
one:
  sm8350-microsoft-surface-duo2.dtb: usb@a6f8800: 'dr_mode' does not match any of the regexes: '^usb@[0-9a-f]+$', 'pinctrl-[0-9]+'

Fixes: c16160cf ("arm64: dts: qcom: add minimal DTS for Microsoft Surface Duo 2")
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Reviewed-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Link: https://lore.kernel.org/r/20230304130315.51595-2-krzysztof.kozlowski@linaro.org