build: fix xconfig target

`make xconfig` fails with following linking error of qconf binary:

 g++ -lQt5Widgets -lQt5Gui -lQt5Core -o qconf qconf.o zconf.tab.o
 /usr/bin/ld: qconf.o: in function ConfigList::metaObject() const': qconf.cc:(.text+0x3eb): undefined reference to QObjectData::dynamicMetaObject() const'
 /usr/bin/ld: qconf.o: in function `ConfigList::qt_metacast(char const*)': link error.

which is caused by the wrong order of the linked objects/libraries so
this patch reorders the linker's arguments which makes the qconf compile
again.

Signed-off-by: leo chung <gewalalb@gmail.com>
[commit subject and message tweaks, whitespace fix]
Signed-off-by: Petr Štetiar <ynezz@true.cz>

scripts/config/Makefile

@@ -40,7 +40,7 @@ mconf: $(mconf-objs) $(lxdialog-objs)
 	$(CC) -o $@ $^ $(call check_lxdialog,ldflags $(CC))
 qconf: $(qconf-cxxobjs) $(qconf-objs)
 ifneq ($(DISTRO-PKG-CONFIG),)
-	$(CXX) $(HOSTLOADLIBES_qconf) -o $@ $^
+	$(CXX) -o $@ $^ $(HOSTLOADLIBES_qconf)
 else
 	echo "You don't have 'pkg-config' installed. Cannot continue"
 	echo "For now, you may use 'make menuconfig' instead of 'make xconfig'"