kernel.h: Fix a typo in comment

Signed-off-by: NWei Wang <wvw@google.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Borislav Petkov <bp@suse.de>
Cc: Crt Mori <cmo@melexis.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: gregkh@linuxfoundation.org
Cc: wei.vince.wang@gmail.com
Link: https://lkml.kernel.org/lkml/20180424212241.16013-1-wvw@google.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

include/linux/kernel.h

@@ -666,7 +666,7 @@ do {									\
  * your code. (Extra memory is used for special buffers that are
  * allocated when trace_printk() is used.)
  *
- * A little optization trick is done here. If there's only one
+ * A little optimization trick is done here. If there's only one
  * argument, there's no need to scan the string for printf formats.
  * The trace_puts() will suffice. But how can we take advantage of
  * using trace_puts() when trace_printk() has only one argument?