tests/qtest/migration: Move kvm_dirty_ring_supported to utils

Move kvm_dirty_ring_supported() to migration-util.c. Similarly to
ufd_version_check(), this function is used during test definition so
put it in the utils file.

Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Fabiano Rosas <farosas@suse.de>
3 files changed