include/linux/once.h: fix trivia typo Not -> Note

Fix trivia typo Not -> Note in the comment to DO_ONCE().

Link: https://lkml.kernel.org/r/20210722184349.76290-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

include/linux/once.h

@@ -16,7 +16,7 @@ void __do_once_done(bool *done, struct static_key_true *once_key,
  * out the condition into a nop. DO_ONCE() guarantees type safety of
  * arguments!
  *
- * Not that the following is not equivalent ...
+ * Note that the following is not equivalent ...
  *
  *   DO_ONCE(func, arg);
  *   DO_ONCE(func, arg);