dt-bindings: soc: xilinx: Add support for KV260 CC

dt-bindings: soc: xilinx: Add support for KV260 CC

When DT overlay is applied at run time compatible string or model AFAIK is
not updated. But when fdtoverlay tool is used it actually creates full
description for used SOM and carrier card(CC). That's why there is no
reason to use generic SOM name and its compatible strings because they are
not properly reflected in newly created DT.
Composing dt overlays together was introduced by commit 7a4c31ee877a
("arm64: zynqmp: Add support for Xilinx Kria SOM board") and later renamed
by commit 45fe0dc4ea2e ("arm64: xilinx: Use zynqmp prefix for SOM dt
overlays").
DTB selection is done prior booting OS that's why there is no need to do
run time composition for SOM and CC combination. And user space can use
compatible string and all listed revisions to figured it out which SOM and
CC combinations OS is running at.

Reviewed-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/14c184225cc4f0a61da5f8c98bc0767f8deba0df.1706019781.git.michal.simek@amd.com
Signed-off-by: Michal Simek <michal.simek@amd.com>