Drop the U-Boot specific DTS in favour of upstream. We'll only include
the -4000 variant as that is what U-Boot already supported.
Taken from kernel tag v6.7
Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Reviewed-by: Sumit Garg <sumit.garg@linaro.org>
Signed-off-by: Caleb Connolly <caleb.connolly@linaro.org>
