Convert the firmware key to a type of autoselected firmware.
Only the 'efi' firmware is allowed for now, in case the key is present.
It seems VMware (at least ESXi) does not write the key in VMX files when
setting BIOS as firmware.
Reviewed-by: Cole Robinson <crobinso@redhat.com>
Signed-off-by: Pino Toscano <ptoscano@redhat.com>
