[SCSI] ipr: Handle UA on disk array following an adapter reset

On certain ipr RAID adapters, which are capable of multi-initiator
configurations, the disk array, or VSET, resources will be in a POR
Unit Attention state following an adapter reset. In order for the
midlayer to handle the UA, I must report a bus reset to the logical
disk array bus at the end of an adapter reset.

Signed-off-by: Brian King <brking@linux.vnet.ibm.com>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>