[SCSI] qla2xxx: Wait for IDC complete event to finish loopback operation.

Wait for the IDC complete AEN before returning the loopback operation back to
the application to make sure the port is put back into normal operations.

Signed-off-by: Chad Dupuis <chad.dupuis@qlogic.com>
Signed-off-by: Saurav Kashyap <saurav.kashyap@qlogic.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>