Makefile: let show-targets prints also the dependencies

Because the "show-targets" target print the targets that will be built,
print also their dependencies.

Signed-off-by: Fabio Porcedda <fabio.porcedda@gmail.com>
Cc: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Cc: "Yann E. MORIN" <yann.morin.1998@free.fr>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

Makefile

@@ -653,7 +653,7 @@ legal-info: dirs legal-info-clean legal-info-prepare $(TARGETS_LEGAL_INFO) \
 	@rm -f $(LEGAL_WARNINGS)
 
 show-targets:
-	@echo $(TARGETS) $(TARGETS_ROOTFS)
+	@echo $(HOST_DEPS) $(TARGETS_HOST_DEPS) $(TARGETS) $(TARGETS_ROOTFS)
 
 graph-build: $(O)/build/build-time.log
 	@install -d $(O)/graphs