PCI: qcom: Make all optional clocks optional

PCI: qcom: Make all optional clocks optional

The kernel is not a devicetree validator and does not need to re-encode
information which is already available in the devicetree.

This is specifically true for the optional PCIe clocks, some of which
are really interconnect clocks.

Treat also the 2.7.0 optional clocks as truly optional instead of
maintaining a list of clocks per compatible (including two compatible
strings for the two identical controllers on sm8450) just to validate
the devicetree.

Link: https://lore.kernel.org/r/20220714071348.6792-7-johan+linaro@kernel.org
Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
Signed-off-by: Lorenzo Pieralisi <lpieralisi@kernel.org>
Reviewed-by: Rob Herring <robh@kernel.org>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Reviewed-by: Brian Masney <bmasney@redhat.com>
Acked-by: Stanimir Varbanov <svarbanov@mm-sol.com>