Now that we have qemuFirmwareGetSupported() so that it also
returns a list of FW image paths, we can use it to report them in
domain capabilities instead of the old time default list.

Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1733940Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>
Reviewed-by: NCole Robinson <crobinso@redhat.com>