drivers: mtd: convert makefiles to Kbuild style

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
diff --git a/drivers/mtd/Makefile b/drivers/mtd/Makefile
index d2c3bda..5467a95 100644
--- a/drivers/mtd/Makefile
+++ b/drivers/mtd/Makefile
@@ -5,38 +5,16 @@
 # SPDX-License-Identifier:	GPL-2.0+
 #
 
-include $(TOPDIR)/config.mk
-
-LIB	:= $(obj)libmtd.o
-
 ifneq (,$(findstring y,$(CONFIG_MTD_DEVICE)$(CONFIG_CMD_NAND)$(CONFIG_CMD_ONENAND)))
-COBJS-y += mtdcore.o
+obj-y += mtdcore.o
 endif
-COBJS-$(CONFIG_MTD_PARTITIONS) += mtdpart.o
-COBJS-$(CONFIG_MTD_CONCAT) += mtdconcat.o
-COBJS-$(CONFIG_HAS_DATAFLASH) += at45.o
-COBJS-$(CONFIG_FLASH_CFI_DRIVER) += cfi_flash.o
-COBJS-$(CONFIG_FLASH_CFI_MTD) += cfi_mtd.o
-COBJS-$(CONFIG_HAS_DATAFLASH) += dataflash.o
-COBJS-$(CONFIG_FTSMC020) += ftsmc020.o
-COBJS-$(CONFIG_FLASH_CFI_LEGACY) += jedec_flash.o
-COBJS-$(CONFIG_MW_EEPROM) += mw_eeprom.o
-COBJS-$(CONFIG_ST_SMI) += st_smi.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_MTD_PARTITIONS) += mtdpart.o
+obj-$(CONFIG_MTD_CONCAT) += mtdconcat.o
+obj-$(CONFIG_HAS_DATAFLASH) += at45.o
+obj-$(CONFIG_FLASH_CFI_DRIVER) += cfi_flash.o
+obj-$(CONFIG_FLASH_CFI_MTD) += cfi_mtd.o
+obj-$(CONFIG_HAS_DATAFLASH) += dataflash.o
+obj-$(CONFIG_FTSMC020) += ftsmc020.o
+obj-$(CONFIG_FLASH_CFI_LEGACY) += jedec_flash.o
+obj-$(CONFIG_MW_EEPROM) += mw_eeprom.o
+obj-$(CONFIG_ST_SMI) += st_smi.o