arm64: dts: qcom: sc8180x: Introduce Lenovo Flex 5G

Introduce support for the Lenovo Flex 5G laptop, built on the Qualcomm
SC8180X platform. Supported peripherals includes keyboard, touchpad,
UFS storage, external USB and WiFi.

Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Link: https://lore.kernel.org/r/20230530162454.51708-16-vkoul@kernel.org