arm64: dts: qcom: Add support for Xiaomi Mi Mix2s

Add support for Xiaomi Mi Mix2s (polaris) handsets.

Currently working features:
- UFS
- Touchscreen
- USB 2
- Bluetooth
- Wi-Fi
- GPU
- Venus
- Display (need jdi-fhd-nt35596s panel driver, which I have sent a
  patch but it haven't been into upstream yet)

Signed-off-by: Molly Sophia <mollysophia379@gmail.com>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/20220712145139.9473-2-mollysophia379@gmail.com