dts, api, test: convert makefiles to Kbuild style

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>

Makefile

@@ -383,7 +383,7 @@ build := -f $(TOPDIR)/scripts/Makefile.build -C
 all:		$(ALL-y) $(SUBDIR_EXAMPLES)
 
 $(obj)u-boot.dtb:	checkdtc $(obj)u-boot
-		$(MAKE) -C dts binary
+		$(MAKE) $(build) dts binary
 		mv $(obj)dts/dt.dtb $@
 
 $(obj)u-boot-dtb.bin:	$(obj)u-boot.bin $(obj)u-boot.dtb

api/Makefile

@@ -4,21 +4,5 @@
 # SPDX-License-Identifier:	GPL-2.0+
 #
 
-include $(TOPDIR)/config.mk
-
-LIB	= $(obj)libapi.o
-
-COBJS-$(CONFIG_API) += api.o api_display.o api_net.o api_storage.o \
+obj-$(CONFIG_API) += api.o api_display.o api_net.o api_storage.o \
 		       api_platform-$(ARCH).o
-
-COBJS	:= $(COBJS-y)
-SRCS	:= $(COBJS:.o=.c)
-OBJS	:= $(addprefix $(obj),$(COBJS))
-
-$(LIB):	$(obj).depend $(OBJS)
-	$(call cmd_link_o_target, $(OBJS))
-
-# defines $(obj).depend target
-include $(SRCTREE)/rules.mk
-
-sinclude $(obj).depend

dts/Makefile

@@ -7,10 +7,6 @@
 # This Makefile builds the internal U-Boot fdt if CONFIG_OF_CONTROL is
 # enabled. See doc/README.fdt-control for more details.
 
-include $(TOPDIR)/config.mk
-
-LIB	= $(obj)libdts.o
-
 ifeq ($(DEVICE_TREE),)
 $(if $(CONFIG_DEFAULT_DEVICE_TREE),,\
 $(error Please define CONFIG_DEFAULT_DEVICE_TREE in your board header file))
@@ -27,8 +23,6 @@ DTS_CPPFLAGS := -x assembler-with-cpp -undef -D__DTS__ \
 DTC_FLAGS := -R 4 -p 0x1000 \
 	$(addprefix -i ,$(DTS_INCDIRS))
 
-all:	$(obj).depend $(LIB)
-
 # Use a constant name for this so we can access it from C code.
 # objcopy doesn't seem to allow us to set the symbol name independently of
 # the filename.
@@ -71,22 +65,6 @@ $(obj)dt.o: $(DT_BIN)
 		$(notdir ${DT_BIN}) $@
 	rm $(DT_BIN)
 
-OBJS-$(CONFIG_OF_EMBED)	:= dt.o
-
-COBJS	:= $(OBJS-y)
-
-OBJS	:= $(addprefix $(obj),$(COBJS))
+obj-$(CONFIG_OF_EMBED)	:= dt.o
 
 binary:	$(DT_BIN)
-
-$(LIB):	$(OBJS) $(DTB)
-	$(call cmd_link_o_target, $(OBJS))
-
-#########################################################################
-
-# defines $(obj).depend target
-include $(SRCTREE)/rules.mk
-
-sinclude $(obj).depend
-
-#########################################################################

test/Makefile

@@ -4,27 +4,5 @@
 # SPDX-License-Identifier:	GPL-2.0+
 #
 
-include $(TOPDIR)/config.mk
-
-LIB	= $(obj)libtest.o
-
-COBJS-$(CONFIG_SANDBOX) += command_ut.o
-COBJS-$(CONFIG_SANDBOX) += compression.o
-
-COBJS	:= $(sort $(COBJS-y))
-SRCS	:= $(COBJS:.o=.c)
-OBJS	:= $(addprefix $(obj),$(COBJS))
-
-all:	$(LIB) $(XOBJS)
-
-$(LIB): $(obj).depend $(OBJS)
-	$(call cmd_link_o_target, $(OBJS))
-
-#########################################################################
-
-# defines $(obj).depend target
-include $(SRCTREE)/rules.mk
-
-sinclude $(obj).depend
-
-#########################################################################
+obj-$(CONFIG_SANDBOX) += command_ut.o
+obj-$(CONFIG_SANDBOX) += compression.o