SoC driver updates for 6.2

There are few major updates in the SoC specific drivers, mainly the usual
reworks and support for variants of the existing SoC.  While this remains
Arm centric for the most part, the branch now also contains updates to
risc-v and loongarch specific code in drivers/soc/.

Notable changes include:

 - Support for the newly added Qualcomm Snapdragon variants
   (MSM8956, MSM8976, SM6115, SM4250, SM8150, SA8155 and SM8550) in the
   soc ID, rpmh, rpm, spm and powerdomain drivers.

 - Documentation for the somewhat controversial qcom,board-id
   properties that are required for booting a number of machines

 - A new SoC identification driver for the loongson-2 (loongarch)
   platform

 - memory controller updates for stm32, tegra, and renesas.

 - a new DT binding to better describe LPDDR2/3/4/5 chips in
   the memory controller subsystem

 - Updates for Tegra specific drivers across multiple subsystems,
   improving support for newer SoCs and better identification

 - Minor fixes for Broadcom, Freescale, Apple, Renesas, Sifive,
   TI, Mediatek and Marvell SoC drivers