Add support to xenconfig for conversion of xl.cfg(5) bios config
to/from libvirt domXml <loader> config. SeaBIOS is the default
for HVM guests using upstream QEMU. ROMBIOS is the default when
using the old qemu-dm. This patch allows specifying OVMF as an
alternate firmware.
Example xl.cfg:
bios = "ovmf"
Example domXML:
<os>
...
<loader readonly='yes' type='pflash'>/usr/lib/xen/boot/ovmf.bin</loader>
</os>
Note that currently Xen does not support a separate nvram for
non-volatile variables.
Signed-off-by: Jim Fehlig <jfehlig@suse.com>