sata_mv: ensure empty request queue for FBS-NCQ EH

Check for an empty request queue before stopping EDMA after a FBS-NCQ error,
as per recommendation from the Marvell datasheet.

This ensures that the EDMA won't suddenly become active again
just after our subsequent check of the empty/idle bits.

Also bump DRV_VERSION.

Signed-off-by: Mark Lord <mlord@pobox.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>