PCI: qcom: Move host bridge 'phy' and 'reset' pointers to struct qcom_pcie_port

DT binding allows specifying 'phy' and 'reset' properties in both host
bridge and Root Port nodes, though specifying in the host bridge node is
marked as deprecated. Still, the pcie-qcom driver should support both
combinations for maintaining the DT backwards compatibility. For this
purpose, the driver is holding the relevant pointers of these properties in
two structs: struct qcom_pcie_port and struct qcom_pcie.

However, this causes confusion and increases the driver complexity. Hence,
move the pointers from struct qcom_pcie to struct qcom_pcie_port. As a
result, even if these properties are specified in the host bridge node,
the pointers will be stored in struct qcom_pcie_port as if the properties
are specified in a single Root Port node. This logic simplifies the driver
a lot.

Suggested-by: Bjorn Helgaas <helgaas@kernel.org>
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@oss.qualcomm.com>
Reviewed-by: Bjorn Helgaas <bhelgaas@google.com>
Link: https://patch.msgid.link/20250912-pci-pwrctrl-perst-v3-2-3c0ac62b032c@oss.qualcomm.com