PCI: qcom-ep: Add ICC bandwidth voting support

Add support for voting interconnect (ICC) bandwidth based
on the link speed and width.

This commit is inspired from the basic interconnect support added
to pcie-qcom driver in commit c4860af8

 ("PCI: qcom: Add basic
interconnect support").

The interconnect support is kept optional to be backward compatible
with legacy device trees.

[kwilczynski: add missing kernel-doc for the icc_mem variable]
Link: https://lore.kernel.org/linux-pci/1689751218-24492-5-git-send-email-quic_krichai@quicinc.com
Signed-off-by: Krishna chaitanya chundru <quic_krichai@quicinc.com>
Signed-off-by: Krzysztof Wilczyński <kwilczynski@kernel.org>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>