arm64: dts: qcom: Add Microsoft Lumia 950 (Talkman) device tree

arm64: dts: qcom: Add Microsoft Lumia 950 (Talkman) device tree

Add device tree support for the Microsoft Lumia 950 smartphone.
It is based on msm8992 and supports booting Linux via a custom
EDK2 port.

Currently it supports:
* Screen console via EFIFB
* Booting via EFI_STUB
* SDHCI
* I2C
* PSCI core bringup

Please note that there is an implementation of EL2 startup
on this board, but it requires the user to resign from
PSCI and use spin-table instead. This revision sticks with
PSCI.

Signed-off-by: Konrad Dybcio <konradybcio@gmail.com>
Link: https://lore.kernel.org/r/20200625182118.131476-14-konradybcio@gmail.com
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>