scsi: qla2xxx: Fix exchange oversubscription for management commands

Add resource checking for management (non-I/O) commands.

Fixes: 89c72f42

 ("scsi: qla2xxx: Add IOCB resource tracking")
Signed-off-by: Quinn Tran <qutran@marvell.com>
Signed-off-by: Nilesh Javali <njavali@marvell.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>