"apple,t6020-sart" as found in Apple's M2 Pro/Max/Ultra SoCs is
compatible with SART3 used in t6000. Add its per-SoC compatible to allow
a distinction should it become necessary.
Reviewed-by: Neal Gompa <neal@gompa.dev> Acked-by: Rob Herring (Arm) <robh@kernel.org> Signed-off-by: Janne Grunau <j@jannau.net>