Copy the devicetree source for the A64 SoC and all existing boards
from the Linux v5.18-rc1 tag.

To maintain ABI compatibility with existing LTS kernels, one change
moving some IP blocks to the r_intc interrupt controller is excluded.
This effectively reverts Linux commits 189bef235dd3 and 73088dfee635.

This update should not impact any existing U-Boot functionality.
Signed-off-by: NSamuel Holland <samuel@sholland.org>