kernel.h: fix a typo in comment

index 6a1eb0b0aad96..e37e40ff14bba 100644
@@ -664,7 +664,7 @@ 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?