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/char/tty_ioctl.c b/drivers/char/tty_ioctl.c
index 0def089..7a00350 100644
--- a/drivers/char/tty_ioctl.c
+++ b/drivers/char/tty_ioctl.c
@@ -444,7 +444,7 @@
  *	@arg: user data
  *	@opt: option information
  *
- *	Helper function to prepare termios data and run neccessary other
+ *	Helper function to prepare termios data and run necessary other
  *	functions before using change_termios to do the actual changes.
  *
  *	Locking: