roms: switch oldnoconfig to olddefconfig

When a new option is added that qemu does not know
about, the prudent thing is to use the default not
force it to "no".

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
diff --git a/roms/configure-seabios.sh b/roms/configure-seabios.sh
index 98f59a2..4bb6c2b 100755
--- a/roms/configure-seabios.sh
+++ b/roms/configure-seabios.sh
@@ -2,4 +2,4 @@
 config="$1"
 make -C seabios clean distclean
 cp "$config" seabios/.config
-make -C seabios oldnoconfig
+make -C seabios olddefconfig