Add a note to the build about the expected parser warnings.

Signed-off-by: Jon Loeliger
diff --git a/Makefile b/Makefile
index a919bfa..6b278b9 100644
--- a/Makefile
+++ b/Makefile
@@ -79,6 +79,7 @@
 
 dtc-parser.tab.c dtc-parser.tab.h dtc-parser.output: dtc-parser.y
 	@$(VECHO) BISON $@
+	@$(VECHO) ---- Expect 2 s/r and 2 r/r. ----
 	$(BISON) -d $<
 
 lex.yy.c: dtc-lexer.l