dt-bindings: PCI: qcom: ep: Add interconnects path

Some platforms may not boot if a device driver doesn't
initialize the interconnect path. Mostly it is handled
by the bootloader but we have starting to see cases
where bootloader simply ignores them.

Add the "pcie-mem" & "cpu-pcie" interconnect path as a required
property to the bindings.

Link: https://lore.kernel.org/linux-pci/1689751218-24492-2-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: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Acked-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>