dt-bindings: arm-smmu: Remove sdm845-cheza specific entry

dt-bindings: arm-smmu: Remove sdm845-cheza specific entry

The firmware on SDM845-based Cheza boards did not provide the same
level of feature support for SMMUs (particularly around the Adreno
GPU integration).

Now that Cheza is being removed from the kernel (almost none exist at
this point in time), retire the entry as well.

Most notably, it's not being marked as deprecated instead, as there is
no indication that any more of those ~7 year old devboards will be
built.

Signed-off-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Acked-by: Robin Murphy <robin.murphy@arm.com>
Link: https://lore.kernel.org/r/20250716-topic-goodnight_cheza-v2-3-6fa8d3261813@oss.qualcomm.com
Signed-off-by: Will Deacon <will@kernel.org>