[SCSI] aic94xx: Remove workqueue code from REQ_TASK_ABORT/REQ_DEVICE_RESET code

Now that task aborts and device port resets are done by the EH, we can
remove all the code that set up workqueues and such and simply call
sas_task_abort and let libsas figure things out.

Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>