dt-bindings: PCI: qcom,pcie-sc8180x: Drop unrelated clocks from PCIe hosts

dt-bindings: PCI: qcom,pcie-sc8180x: Drop unrelated clocks from PCIe hosts

The TBU clock belongs to the Translation Buffer Unit, part of the SMMU.
The ref clock is already being driven upstream through some of the
branches.

Signed-off-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>
Signed-off-by: Manivannan Sadhasivam <mani@kernel.org>
Acked-by: Rob Herring (Arm) <robh@kernel.org>
Link: https://patch.msgid.link/20250521-topic-8150_pcie_drop_clocks-v1-1-3d42e84f6453@oss.qualcomm.com