[SCSI] libsas: defer SAS_TASK_NEED_DEV_RESET commands to libata

lldds use the SAS_TASK_NEED_DEV_RESET interface to request that eh
perform a reset.  In the sata device case defer the commands that
triggered the reset to libata-eh context so it can perform its pre and
post reset management.

In the sas_ata_post_internal() case the reset request is falling on deaf
ears as the sas_task is immediately destroyed without any reset action.
Since it is currently a nop, and likely superfluous given the conversion
to new-style libata-eh, just drop the request.

Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>