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/ata/pata_via.c

@@ -420,7 +420,7 @@ static struct ata_port_operations via_port_ops_noirq = {
  *	@pdev: PCI device
  *	@flags: configuration flags
  *
- *	Set the FIFO properties for this device if neccessary. Used both on
+ *	Set the FIFO properties for this device if necessary. Used both on
  *	set up and on and the resume path
  */