CVE-2026-98474: s390/pci: Fix missing device lock in zpci_report_status()

In the Linux kernel, the following vulnerability has been resolved: s390/pci: Fix missing device lock in zpci_report_status() When pdev is non-NULL, zpci_report_status() accesses the device's driver. To get a consistent state matching the recovery, the device lock needs to be held. Do so by expanding the existing device lock critical section. The lock only needs to be held when the pdev is non-NULL, so extract the pdev-specific reporting into a helper function which also adds a lockdep assertion to detect calls without the device lock held.