arm64: dts: qcom: msm8916: add msm8916-common.dtsi

[wonderfulShrineMaidenOfParadise]

The commits add support for Qualcomm MSM8939 SoC with
support for peripherals like I2C, eMMC, WLAN, MDSS and
so on.
The chip is largely based on MSM8916, allowing us to
reuse many of the drivers.

MSM8939 and MSM8916 are similar, with some differences in CPU cores, GPU and clocks,.
The common parts are shared in msm8916-common.dtsi to reduce duplication.

Sadly, it is not capable of using PSCI, but it is possible
to bring up all eight cores with a different approach.

[stephan-gh]

Thanks for the changes! Right now I'm not comfortable merging this "downstream" into msm8916-mainline, as it diverges too much from what Bryan is working on at Linaro (which is semi-actively being upstreamed).

Having such a common dtsi is something I'd like to consider for a wider range of platforms (at least MSM8916+MSM8939+MSM8909). But it's also untypical for Qualcomm platforms upstream so I imagine getting this in needs careful consideration and very good reasoning. I haven't found time yet to think about this myself in detail though.

If you'd like to work on this further I suggest that you coordinate with Bryan since this is definitely not something we can decide alone here in msm8916-mainline.

[wonderfulShrineMaidenOfParadise]

To be honest I am not a fan of Bryan's solution. I might suggest the common dtsi after his patches applied.

[Boom-Hacker]

I think it is very harmful for human to look up the code, even if it may be beneficial for compilation.
such as this arch:https://github.com/LineageOS/android_kernel_huawei_kiwi/tree/lineage-17.1/arch/arm/boot/dts/qcom