Firecracker advertised a broken ACPI PCI hot-plug path

f3f65a3425f6 (Ilias Stamatis, 2026-08-26). src/vmm/src/devices/pci/pci_segment.rs. Drop the dead ACPI PCI hot-plug AML. The tables described an eject method per slot plus two change-notify methods, all calling helper device SB.PHPR that Firecracker never put in the tables. A guest kernel built with ACPI PCI hot-plug then got slot entries whose eject path could only fail. Dropping them removes the dead path. Fixes ancestor 06a88bf94 (removed the unused up/down state). x86_64 ACPI only. FC HEAD is now f3f65a34 (v1.16.1). This is not the device-hotplug-during-reset hang and not the BAR relocate.