PCI: qcom: Use PCIE_SPEED2MBS_ENC() macro for encoding link speed

Instead of hardcoding the link speed in MBps, use existing
PCIE_SPEED2MBS_ENC() macro that does the encoding of the link speed for
us. Also, let's Wrap it with QCOM_PCIE_LINK_SPEED_TO_BW() macro to do
the conversion to ICC speed.

This eliminates the need for a switch case in qcom_pcie_icc_update() and
also works for future Gen speeds without any code modifications.

Suggested-by: Bjorn Helgaas <bhelgaas@google.com>
Link: https://lore.kernel.org/linux-pci/20231004164430.39662-1-manivannan.sadhasivam@linaro.org


Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: Krzysztof Wilczyński <kwilczynski@kernel.org>
Reviewed-by: Konrad Dybcio <konrad.dybcio@linaro.org>