scsi: ipr: Error path locking fixes

This patch closes up some potential race conditions observed in the
error handling paths in ipr while debugging an issue resulting in a hang
with SATA error handling. These patches ensure we are holding the
correct lock when adding and removing commands from the free and pending
queues in some error scenarios.

Signed-off-by: Brian King <brking@linux.vnet.ibm.com>
Reviewed-by: Wendy Xiong <wenxiong@linux.vnet.ibm.com>
Tested-by: Wendy Xiong <wenxiong@linux.vnet.ibm.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>