Don't warn if the archive has to be created.

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@23013 a1c6a512-1295-4272-9138-f99709370657
diff --git a/rbutil/mkamsboot/Makefile b/rbutil/mkamsboot/Makefile
index bc70255..7c46a42 100644
--- a/rbutil/mkamsboot/Makefile
+++ b/rbutil/mkamsboot/Makefile
@@ -60,7 +60,7 @@
 
 libmkamsboot$(RBARCH).a: $(OUT) $(OUT)/libmkamsboot.o $(OUT)/md5.o $(OUT)/dualboot.o
 	@echo AR $@
-	$(SILENT)$(AR) ru $(TARGET_DIR)libmkamsboot$(RBARCH).a $(OUT)/libmkamsboot.o $(OUT)/md5.o $(OUT)/dualboot.o
+	$(SILENT)$(AR) ruc $(TARGET_DIR)libmkamsboot$(RBARCH).a $(OUT)/libmkamsboot.o $(OUT)/md5.o $(OUT)/dualboot.o
 
 # some trickery to build ppc and i386 from a single call
 ifeq ($(RBARCH),)