xilinx-ppc4xx-generic: Fix Makefile to work with MAKEALL

config.mk only mkdirs $(obj), but we have objects shared with other
boards located on other dirs.

This patch mkdirs the needed dirs for the xlnx-generic boards.

Signed-off-by: Stefan Roese <sr@denx.de>
diff --git a/board/xilinx/ppc405-generic/Makefile b/board/xilinx/ppc405-generic/Makefile
index 717ffc9..501fd46 100644
--- a/board/xilinx/ppc405-generic/Makefile
+++ b/board/xilinx/ppc405-generic/Makefile
@@ -27,12 +27,9 @@
 
 include $(TOPDIR)/config.mk
 ifneq ($(OBJTREE),$(SRCTREE))
+$(shell mkdir -p $(obj)../../xilinx/ppc405-generic)
 endif
 
-INCS		:=
-CFLAGS		+= $(INCS)
-HOSTCFLAGS	+= $(INCS)
-
 LIB	= $(obj)lib$(BOARD).o
 
 COBJS	+= ../../xilinx/ppc405-generic/xilinx_ppc405_generic.o
@@ -41,10 +38,8 @@
 OBJS	:= $(addprefix $(obj),$(COBJS))
 SOBJS	:= $(addprefix $(obj),$(SOBJS))
 
-all: $(LIB) $(SOBJS)
-
-$(LIB):	$(OBJS)
-	$(call cmd_link_o_target, $^)
+$(LIB):	$(obj).depend $(OBJS) $(SOBJS)
+	$(call cmd_link_o_target, $(OBJS))
 
 clean:
 	rm -f $(SOBJS) $(OBJS)