[SCSI] qla2xxx: fix lock imbalance

Stanse found that one error path in qla24xx_bsg_timeout omits to
unlock ha->hardware_lock. Fix that.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Acked-by: Giridhar Malavali <giridhar.malavali@qlogic.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>