Merge branch 'pci/endpoint/doorbell'

Merge branch 'pci/endpoint/doorbell'

- Add RC-to-EP doorbell support using platform MSI controller (Frank Li)

- Check for MSI parent and mutability since we currently don't support
  mutable MSI controllers (Frank Li)

- Add pci_epf_align_inbound_addr() helper (Frank Li)

- Add a doorbell test (Frank Li)

* pci/endpoint/doorbell:
  selftests: pci_endpoint: Add doorbell test case
  misc: pci_endpoint_test: Add doorbell test case
  PCI: endpoint: pci-epf-test: Add doorbell test support
  PCI: endpoint: Add pci_epf_align_inbound_addr() helper for inbound address alignment
  PCI: endpoint: pci-ep-msi: Add checks for MSI parent and mutability
  PCI: endpoint: Add RC-to-EP doorbell support using platform MSI controller