dt-bindings: arm-smmu: Fix SDM630 clocks description

SDM630 was abusingly referencing one of the internal bus clocks, that
were recently dropped from Linux (because the original implementation
did not make much sense), circumventing the interconnect framework.

Fix it by dropping the bus-mm clock (which requires separating 630 from
similar entries) and keeping the rest as-is.

Signed-off-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Link: https://lore.kernel.org/r/20230721-topic-rpm_clk_cleanup-v2-4-1e506593b1bd@linaro.org
Signed-off-by: Will Deacon <will@kernel.org>