arm-bsp/u-boot: cs1k: Align Ethos-U85 DT with in-tree driver

Align the Corstone1000 Ethos-U85 device tree to match the upstream
bindings used by the in-tree Ethos-U DRM accel driver.

- Rework the Corstone1000 U-Boot patch to replace the legacy arm,ethosu-direct
  node with an upstream-style Ethos-U85 node (arm,ethos-u85), add the
  required clocks/clock-names, and switch the SRAM description to
  mmio-sram.

- Drop meta-ethos specific properties (reserved-memory/dma-ranges,
/region-cfgs/mem-config) from the U-Boot DT.

- Enable required kernel options for the in-tree driver and SRAM provider:
  - CONFIG_SRAM
  - CONFIG_DRM
  - CONFIG_DRM_ACCEL
  - CONFIG_DRM_ACCEL_ARM_ETHOSU

Signed-off-by: Michael Safwat <michael.safwat@arm.com>
Signed-off-by: Frazer Carsley <frazer.carsley@arm.com>
Signed-off-by: Jon Mason <jon.mason@arm.com>

meta-arm-bsp/recipes-kernel/linux/files/corstone1000/ethosu.cfg

@@ -0,0 +1,4 @@
+CONFIG_SRAM=y
+CONFIG_DRM=y
+CONFIG_DRM_ACCEL=y
+CONFIG_DRM_ACCEL_ARM_ETHOSU=y

meta-arm-bsp/recipes-kernel/linux/linux-arm-platforms.inc

@@ -65,6 +65,7 @@ KMACHINE:corstone1000:cortexa320 = "corstone1000-a320"
 LINUX_KERNEL_TYPE:corstone1000:cortexa320 = "standard"
 SRC_URI:append:corstone1000:cortexa320 = " \
     file://defconfig  \
+    file://ethosu.cfg \
 "
 
 # Default kernel features not needed for Corstone-1000 with