We already allow users to provide TFTP root path in network XML
and not specify any DHCP. This makes sense, because dnsmasq is
not only DHCP server but also TFTP server and users might have
a DHCP server configured on their own, outside of libvirt's
control and want just the TFTP part.
By moving TFTP config generator out of DHCP generator and calling
it for every IPv4 range, users can finally enable just TFTP.
Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=2026765
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>