m501sk: Fix out of tree building

Signed-off-by: Wolfgang Denk <wd@denx.de>

board/m501sk/Makefile

@@ -23,12 +23,16 @@
 
 include $(TOPDIR)/config.mk
 
-LIB    = lib$(BOARD).a
+LIB	= $(obj)lib$(BOARD).a
 
-OBJS   := m501sk.o eeprom.o
+COBJS  := m501sk.o eeprom.o
 
 SOBJS  := memsetup.o
 
+SRCS	:= $(SOBJS:.o=.S) $(COBJS:.o=.c)
+OBJS	:= $(addprefix $(obj),$(COBJS))
+SOBJS	:= $(addprefix $(obj),$(SOBJS))
+
 $(LIB):	$(OBJS) $(SOBJS)
 	$(AR) crv $@ $(OBJS) $(SOBJS)
 
@@ -40,9 +44,9 @@ distclean:     clean
 
 #########################################################################
 
-.depend:	Makefile $(SOBJS:.o=.S) $(OBJS:.o=.c)
-		$(CC) -M $(CPPFLAGS) $(SOBJS:.o=.S) $(OBJS:.o=.c) > $@
+# defines $(obj).depend target
+include $(SRCTREE)/rules.mk
 
--include .depend
+sinclude $(obj).depend
 
 #########################################################################