tools: ynl: add distclean to .PHONY in all makefiles

Donald points out most YNL makefiles are missing distclean
in .PHONY, even tho generated/Makefile does list it.
Suggested-by: Donald Hunter <donald.hunter@gmail.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Reviewed-by: Donald Hunter <donald.hunter@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

tools/net/ynl/Makefile

@@ -18,4 +18,4 @@ clean distclean:
 		fi \
 	done
 
-.PHONY: clean all $(SUBDIRS)
+.PHONY: all clean distclean $(SUBDIRS)

tools/net/ynl/lib/Makefile

@@ -24,5 +24,5 @@ distclean: clean
 %.o: %.c
 	$(COMPILE.c) -MMD -c -o $@ $<
 
-.PHONY: all clean
+.PHONY: all clean distclean
 .DEFAULT_GOAL=all

tools/net/ynl/samples/Makefile

@@ -31,5 +31,5 @@ clean:
 distclean: clean
 	rm -f $(BINS)
 
-.PHONY: all clean
+.PHONY: all clean distclean
 .DEFAULT_GOAL=all