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>
diff --git a/drivers/ata/ahci.c b/drivers/ata/ahci.c
index 10bc3f6..47c8060 100644
--- a/drivers/ata/ahci.c
+++ b/drivers/ata/ahci.c
@@ -1479,7 +1479,7 @@
 		return;
 	}
 
-	/* hmmm... a spurious interupt */
+	/* hmmm... a spurious interrupt */
 
 	/* if !NCQ, ignore.  No modern ATA device has broken HSM
 	 * implementation for non-NCQ commands.