ntp: fix comment typos

Bernhard Schiffner noticed I had a few comment typos in this patch,
(note: to save embarrassment, when making typos, avoid copying and
pasting them) so this patch corrects them.

[ Impact: cleanup ]

Reported-by: Bernhard Schiffner <bernhard@schiffner-limbach.de>
Signed-off-by: John Stultz <johnstul@us.ibm.com>
Cc: riel@redhat.com
Cc: akpm@linux-foundation.org
LKML-Reference: <1242090794.7214.131.camel@localhost.localdomain>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

include/linux/timex.h

@@ -179,7 +179,7 @@ struct timex {
  * NTP convergence time. A higher value makes it stiffer, increasing
  * convergence time, but making the clock more stable.
  *
- * In David Mills' nanokenrel reference implmentation SHIFT_PLL is 4.
+ * In David Mills' nanokernel reference implementation SHIFT_PLL is 4.
  * However this seems to increase convergence time much too long.
  *
  * https://lists.ntp.org/pipermail/hackers/2008-January/003487.html
@@ -196,7 +196,7 @@ struct timex {
  *
  * SHIFT_FLL is used as a dampening factor to define how much we
  * adjust the frequency correction for a given offset in FLL mode.
- * In David Mills' nanokenrel reference implmentation SHIFT_PLL is 2.
+ * In David Mills' nanokernel reference implementation SHIFT_FLL is 2.
  *
  * MAXTC establishes the maximum time constant of the PLL.
  */