scsi: qla2xxx: Remove a comment that refers to the SCSI host lock

Since qla2xxx_queuecommand() no longer takes the SCSI host lock, remove a
comment that refers to the host lock.

Cc: Himanshu Madhani <hmadhani@marvell.com>
Cc: Giridhar Malavali <gmalavali@marvell.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Acked-by: Himanshu Madhani <hmadhani@marvell.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>