Fix misspellings of "system", "controller", "interrupt" and "necessary".

Fix the various misspellings of "system", controller", "interrupt" and
"[un]necessary".

Signed-off-by: Robert P. J. Day <rpjday@mindspring.com>
Signed-off-by: Adrian Bunk <bunk@kernel.org>

drivers/scsi/qla4xxx/ql4_init.c

@@ -1006,7 +1006,7 @@ int ql4xxx_lock_drvr_wait(struct scsi_qla_host *a)
  * qla4xxx_start_firmware - starts qla4xxx firmware
  * @ha: Pointer to host adapter structure.
  *
- * This routine performs the neccessary steps to start the firmware for
+ * This routine performs the necessary steps to start the firmware for
  * the QLA4010 adapter.
  **/
 static int qla4xxx_start_firmware(struct scsi_qla_host *ha)