[SCSI] qla2xxx: Fix Task Management command asynchronous handling

- Fix interpreting the wrong IOCB type for task management
functions in the response path.
- Merge the task management function handling for various adapters.

Signed-off-by: Armen Baloyan <armen.baloyan@qlogic.com>
Signed-off-by: Saurav Kashyap <saurav.kashyap@qlogic.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>