board: powerpc: convert makefiles to Kbuild style

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Cc: Wolfgang Denk <wd@denx.de>
Cc: Kim Phillips <kim.phillips@freescale.com>
Cc: York Sun <yorksun@freescale.com>
Cc: Stefan Roese <sr@denx.de>
diff --git a/board/cray/L1/Makefile b/board/cray/L1/Makefile
index 9e6461a..5f6c690 100644
--- a/board/cray/L1/Makefile
+++ b/board/cray/L1/Makefile
@@ -5,36 +5,12 @@
 # SPDX-License-Identifier:	GPL-2.0+
 #
 
-include $(TOPDIR)/config.mk
-
-LIB	= $(obj)lib$(BOARD).o
-
-COBJS	= $(BOARD).o flash.o
-SOBJS	= init.o
-
-
-SRCS	:= $(SOBJS:.o=.S) $(COBJS:.o=.c)
-OBJS	:= $(addprefix $(obj),$(COBJS))
-SOBJS	:= $(addprefix $(obj),$(SOBJS))
-
-# HACK: depend needs bootscript.c, which needs tools/mkimage, which is not
-# built in the depend stage.  So... put bootscript.o here, not in OBJS
-$(LIB):	$(OBJS) $(SOBJS) $(obj)bootscript.o
-	$(call cmd_link_o_target, $^)
-
-$(obj)$(BOARD).o : $(src)$(BOARD).c $(obj)bootscript.o
+obj-y	= L1.o flash.o
+obj-y	+= init.o
+obj-y	+= bootscript.o
 
 $(obj)bootscript.c: $(obj)bootscript.image
 	od -t x1 -v -A x $^ | awk -f x2c.awk > $@
 
 $(obj)bootscript.image: $(src)bootscript.hush $(src)Makefile
 	-$(OBJTREE)/tools/mkimage -A ppc -O linux -T script -C none -a 0 -e 0 -n bootscript -d $(src)bootscript.hush $@
-
-#########################################################################
-
-# defines $(obj).depend target
-include $(SRCTREE)/rules.mk
-
-sinclude $(obj).depend
-
-#########################################################################