Fix the compile of disabled DEBUG_PARSING code.

cherry-picked from master
diff --git a/src/mesa/shader/prog_parameter.c b/src/mesa/shader/prog_parameter.c
index bb96427..4eb7313 100644
--- a/src/mesa/shader/prog_parameter.c
+++ b/src/mesa/shader/prog_parameter.c
@@ -387,7 +387,7 @@
  *    PARAM ambient = state.material.front.ambient;
  *
  * \param paramList  the parameter list
- * \param state  an array of 6 (STATE_LENGTH) state tokens
+ * \param stateTokens  an array of 5 (STATE_LENGTH) state tokens
  * \return index of the new parameter.
  */
 GLint