Don't immediately abort .start if DMA is busy before we
initialize the queues. Some drivers do not deinitialize
queues properly and we would fail to take over after them.

This behaviour is consistent with legacy driver.
Signed-off-by: Jakub Kicinski <kubakici@wp.pl>
Acked-by: Gertjan van Wingerde <gwingerde@gmail.com>
Reviewed-by: Stanislaw Gruszka <sgruszka@redhat.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>