feat: e1000d MSI/MSI-X migration — use pci_allocate_interrupt_vector

e1000d was the last NIC driver using legacy IRQ (irq.irq_handle()).
Migrated to pci_allocate_interrupt_vector which tries MSI-X first,
then MSI, then falls back to legacy INTx — matching rtl8168d, rtl8139d,
ihdad, ihdgd, and nvmed.

63-line patch at local/patches/base/P6-e1000d-msi-migration.patch,
symlinked and wired into recipes/core/base/recipe.toml.

recipes/core/base/recipe.toml

@@ -5,6 +5,7 @@ patches = [
     "P0-daemon-fix-init-notify-unwrap.patch",
     "P0-workspace-add-bootstrap.patch",
     "P0-init-continuous-scheduling.patch",
+    "P6-e1000d-msi-migration.patch",
 # TODO: P1 patches (11) exist in local/patches/base/ but need rebase
 # after redox.patch removal. ACPI (5), PCI/IRQ (3), xHCI (3) — 1144 lines.
 #   P1-acpid-acpi-core.patch