Switch to efi-enabled nic roms by default

Switch to efi-enabled nic roms by default

All PCI nics are switched to EFI-enabled roms by default.  They are
composed from three images (legacy, efi ia32 & efi x86), so classic
pxe booting will continue to work.

Exception: eepro100 is not switched, it uses a single rom for all
emulated eepro100 variants, then goes patch the rom header on the
fly with the correct PCI IDs.  I doubt that will work as-is with
the efi roms.

Keep old roms for 1.4+older machine types via compat properties,
needed because the efi-enabled roms are larger so the pci rom bar
size would change.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>