Rebuild libfdt shared object if versioning linker script changes

The usable content of the shared library varies depending on the symbol
versions given in the version.lds linker script, however it's not currently
in the make dependencies.  Correct that, and move the libfdt rules together
for consistency while we're at it.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>

Makefile

@@ -194,7 +194,11 @@ include $(LIBFDT_dir)/Makefile.libfdt
 libfdt: $(LIBFDT_archive) $(LIBFDT_lib)
 
 $(LIBFDT_archive): $(addprefix $(LIBFDT_dir)/,$(LIBFDT_OBJS))
-$(LIBFDT_lib): $(addprefix $(LIBFDT_dir)/,$(LIBFDT_OBJS))
+
+$(LIBFDT_lib): $(addprefix $(LIBFDT_dir)/,$(LIBFDT_OBJS)) $(LIBFDT_version)
+	@$(VECHO) LD $@
+	$(CC) $(LDFLAGS) $(SHAREDLIB_LDFLAGS)$(LIBFDT_soname) -o $(LIBFDT_lib) \
+		$(addprefix $(LIBFDT_dir)/,$(LIBFDT_OBJS))
 
 ifneq ($(DEPTARGETS),)
 -include $(LIBFDT_OBJS:%.o=$(LIBFDT_dir)/%.d)
@@ -356,10 +360,6 @@ clean: libfdt_clean pylibfdt_clean tests_clean
 	@$(VECHO) AR $@
 	$(AR) $(ARFLAGS) $@ $^
 
-$(LIBFDT_lib):
-	@$(VECHO) LD $@
-	$(CC) $(LDFLAGS) $(SHAREDLIB_LDFLAGS)$(LIBFDT_soname) -o $(LIBFDT_lib) $^
-
 %.lex.c: %.l
 	@$(VECHO) LEX $@
 	$(LEX) -o$@ $<