feat(stm32mp15-fdts): add Avenger96 board with STM32MP157A DHCOR SoM

This should replace the stm32mp157a-avenger96.dts with the new device
tree files split into the STM32MP15 DHCOR SoM definition and the
Avenger96 baseboard like it's done in Linux and U-Boot.

Differences to stm32mp157a-avenger96.dts:
- Enable sdmmc2 for booting from eMMC
- improved clock settings like in U-Boot commit b6055945
  "ARM: dts: stm32: Adjust PLL4 settings on AV96 again"
- improved DDR settings for DHSOMs like in U-Boot commit 92ca0f74
  "ARM: dts: stm32: Synchronize DDR setttings on DH SoMs"

TF-A with this new dts(i) files on this board was fully tested with
the latest OP-TEE developer setup.

Change-Id: I85ce8eca7747965af3555fc19fd7b192dc3e5740
Signed-off-by: Johann Neuhauser <jneuhauser@dh-electronics.com>
6 files changed