[PATCH] aic94xx: handle REQ_DEVICE_RESET

This patch implements a REQ_DEVICE_RESET handler for the aic94xx
driver.  Like the earlier REQ_TASK_ABORT patch, this patch defers the
device reset to the Scsi_Host's workqueue, which has the added benefit
of ensuring that the device reset does not happen at the same time
that the abort tmfs are being processed.  After the phy reset, the
busted drive should go away and be re-detected later, which is indeed
what I've seen on both a x260 and a x206m.

Signed-off-by: Darrick J. Wong <djwong@us.ibm.com>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>