arm64: dts: qcom: sdm630: Add USB configuration

This will let us use USB2 on our devices. The SoC
supposedly supports USB3, but there are no known
cases of devices that actually have USB3 wired up in
hardware.

Signed-off-by: Konrad Dybcio <konrad.dybcio@somainline.org>
Link: https://lore.kernel.org/r/20210728222542.54269-8-konrad.dybcio@somainline.org
[bjorn: Changes dwc3 node name to "usb"]
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>