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/n_tty.c b/drivers/char/n_tty.c
index 0380569..596c717 100644
--- a/drivers/char/n_tty.c
+++ b/drivers/char/n_tty.c
@@ -437,7 +437,7 @@
  *	@c: character input
  *	@tty: terminal device
  *
- *	Perform erase and neccessary output when an erase character is
+ *	Perform erase and necessary output when an erase character is
  *	present in the stream from the driver layer. Handles the complexities
  *	of UTF-8 multibyte symbols.
  */
@@ -657,7 +657,7 @@
  *	@c: character
  *
  *	Process a parity error and queue the right data to indicate
- *	the error case if neccessary. Locking as per n_tty_receive_buf.
+ *	the error case if necessary. Locking as per n_tty_receive_buf.
  */
 static inline void n_tty_receive_parity_error(struct tty_struct *tty,
 					      unsigned char c)