qemuFirmwareMatchDomain: Don't base firmware selection on nvram image format

qemuFirmwareMatchDomain: Don't base firmware selection on nvram image format

Basing the selection on the format of the actual NVRAM image makes no
sense as user may format the image themselves.

Additionally it doesn't make much sense to even limit the firmware
selection based on the nvram template itself. As format of the template
is given and firmware images don't really provide any choice.

Remove the limitation so that autoselection can pick a template
regardless of the selected format or template format.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>