arm64: dts: qcom: sm6115: Add basic soc dtsi

Add support for Qualcomm SM6115 SoC. This includes:
- GCC
- Pinctrl
- RPM (CC+PD)
- USB
- MMC
- UFS

Signed-off-by: Iskren Chernev <iskren.chernev@gmail.com>
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Link: https://lore.kernel.org/r/20220919180618.1840194-7-iskren.chernev@gmail.com