PCI: qcom: Initialize DWC MSI lock for firmware-managed ECAM hosts

PCI: qcom: Initialize DWC MSI lock for firmware-managed ECAM hosts

A lockdep warning is observed during boot on a Qcom firmware-managed
platform:

  INFO: trying to register non-static key.
  The code is fine but needs lockdep annotation, or maybe
  you didn't initialize this object before use?
  turning off the locking correctness validator.
  ...
  Call trace:
   register_lock_class+0x128/0x4d8
   __lock_acquire+0x110/0x1db0
   lock_acquire+0x278/0x3d8
   _raw_spin_lock_irq+0x6c/0xc0
   dw_pcie_irq_domain_alloc+0x48/0x190
   irq_domain_alloc_irqs_parent+0x2c/0x48
   msi_domain_alloc+0x90/0x160
  ...

dw_pcie_irq_domain_alloc() takes pp->lock while allocating MSI
interrupts. pp->lock is normally initialized by dw_pcie_host_init(), but
Qcom firmware-managed hosts use the ECAM init path instead:

  pci_host_common_ecam_create()
    pci_ecam_create()
      qcom_pcie_ecam_host_init()
        dw_pcie_msi_host_init()
          dw_pcie_allocate_domains()

That path constructs a fresh struct dw_pcie_rp and calls
dw_pcie_msi_host_init() directly, without going through
dw_pcie_host_init(). As a result, pp->lock was not initialized, which
triggers the warning.

Initialize pp->lock in qcom_pcie_ecam_host_init() before registering the
MSI domains so the firmware-managed ECAM path matches the normal DWC host
initialization sequence.

Fixes: 7d944c0f1469 ("PCI: qcom: Add support for Qualcomm SA8255p based PCIe Root Complex")
Signed-off-by: Yadu M G <yadu.mg@oss.qualcomm.com>
[mani: added fixes tag and CCed stable]
Signed-off-by: Manivannan Sadhasivam <mani@kernel.org>
Cc: stable@kernel.org
Link: https://patch.msgid.link/20260604122418.727274-1-yadu.mg@oss.qualcomm.com