disk: convert a makefile to Kbuild style

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

disk/Makefile

@@ -5,33 +5,11 @@
 # SPDX-License-Identifier:	GPL-2.0+
 #
 
-include $(TOPDIR)/config.mk
-
 #CFLAGS += -DET_DEBUG -DDEBUG
 
-LIB	= $(obj)libdisk.o
-
-COBJS-$(CONFIG_PARTITIONS) 	+= part.o
-COBJS-$(CONFIG_MAC_PARTITION)   += part_mac.o
-COBJS-$(CONFIG_DOS_PARTITION)   += part_dos.o
-COBJS-$(CONFIG_ISO_PARTITION)   += part_iso.o
-COBJS-$(CONFIG_AMIGA_PARTITION) += part_amiga.o
-COBJS-$(CONFIG_EFI_PARTITION)   += part_efi.o
-
-COBJS	:= $(COBJS-y)
-SRCS	:= $(COBJS:.o=.c)
-OBJS	:= $(addprefix $(obj),$(COBJS))
-
-all:	$(LIB)
-
-$(LIB):	$(obj).depend $(OBJS)
-	$(call cmd_link_o_target, $(OBJS))
-
-#########################################################################
-
-# defines $(obj).depend target
-include $(SRCTREE)/rules.mk
-
-sinclude $(obj).depend
-
-#########################################################################
+obj-$(CONFIG_PARTITIONS) 	+= part.o
+obj-$(CONFIG_MAC_PARTITION)   += part_mac.o
+obj-$(CONFIG_DOS_PARTITION)   += part_dos.o
+obj-$(CONFIG_ISO_PARTITION)   += part_iso.o
+obj-$(CONFIG_AMIGA_PARTITION) += part_amiga.o
+obj-$(CONFIG_EFI_PARTITION)   += part_efi.o