Merge tag 'u-boot-socfpga-next-20250808' of https://source.denx.de/u-boot/custodians...

Merge tag 'u-boot-socfpga-next-20250808' of https://source.denx.de/u-boot/custodians/u-boot-socfpga

This pull request introduces initial U-Boot support for Agilex7 M-series, along
with several enhancements and cleanups across existing Agilex platforms. Key
changes include new board support, DDR driver additions, updated device trees,
and broader SoCFPGA SPL improvements.

Highlights:

- Agilex7 M-series bring-up:
  - Basic DT support and board initialization for Agilex7 M-series SoC and
    SoCDK.
  - New sdram_agilex7m DDR driver with UIBSSM mailbox support and HBM support.
  - Clock driver support for Agilex7 M-series.
  - New defconfig: socfpga_agilex7m_defconfig.
- Agilex and Agilex5 enhancements:
  - Improved SPL support: ASYNC interrupt enabling, system manager init
    refactor, and cold scratch register usage.
  - Updated firewall probing and watchdog support in SPL.
  - Cleaned up DDR code, added secure region support for ATF, and improved warm
    reset handling.
- Device Tree and config updates:
  - Migration to upstream Linux DT layout for Agilex platforms.
  - Consolidated socfpga_agilex_defconfig and removed deprecated configs.
  - Platform-specific environment variables for Distro Boot added.
- Driver fixes and cleanups:
  - dwc_eth_xgmac and clk-agilex cleanup and improvements.
  - Several coverity and style fixes.

Contributions in this PR are from Alif Zakuan Yuslaimi, Tingting Meng, and
Andrew Goodbody.  This patch set has been tested on Agilex 5 devkit, Agilex
devkit and Agilex7m devkit.

Passing all pipeline tests at SoCFPGA U-boot custodian
https://source.denx.de/u-boot/custodians/u-boot-socfpga/-/pipelines/27318