arm64: dts: qcom: msm8996: Sanitize pins

In order to prepare for feature development, the DTs
have to be workable with.. To achieve that:

- Rename msmgpio to tlmm (consistency with newer DTs)
- Rid msm8996-pins.dtsi and add the contents to msm8996.dtsi
- Modernize the pin nodes, make them more concise
- Add generic pin configuration for some hardware
- Fix up some names in preparation for BLSP/UART name cleaning..

Signed-off-by: Konrad Dybcio <konrad.dybcio@somainline.org>
Link: https://lore.kernel.org/r/20210228130831.203765-1-konrad.dybcio@somainline.org
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>