riscv: kconfig: Imply DM support for some common drivers

This implies DM support for some common drivers that are used on
RISC-V.
Signed-off-by: NBin Meng <bmeng.cn@gmail.com>
Reviewed-by: NLukas Auer <lukas.auer@aisec.fraunhofer.de>

arch/Kconfig

@@ -64,6 +64,15 @@ config RISCV
 	select SUPPORT_OF_CONTROL
 	select OF_CONTROL
 	select DM
+	imply DM_SERIAL
+	imply DM_ETH
+	imply DM_MMC
+	imply DM_SPI
+	imply DM_SPI_FLASH
+	imply BLK
+	imply CLK
+	imply MTD
+	imply TIMER
 	imply CMD_DM
 
 config SANDBOX

configs/ax25-ae350_defconfig

@@ -19,24 +19,16 @@ CONFIG_OF_BOARD=y
 CONFIG_DEFAULT_DEVICE_TREE="ae350"
 CONFIG_ENV_IS_IN_SPI_FLASH=y
 CONFIG_NET_RANDOM_ETHADDR=y
-CONFIG_CLK=y
 CONFIG_MMC=y
-CONFIG_DM_MMC=y
 CONFIG_FTSDC010=y
 CONFIG_FTSDC010_SDIO=y
-CONFIG_MTD=y
 CONFIG_MTD_NOR_FLASH=y
 CONFIG_CFI_FLASH=y
-CONFIG_DM_SPI_FLASH=y
 CONFIG_SPI_FLASH=y
 CONFIG_SPI_FLASH_MACRONIX=y
-CONFIG_DM_ETH=y
 CONFIG_FTMAC100=y
 CONFIG_BAUDRATE=38400
-CONFIG_DM_SERIAL=y
 CONFIG_SYS_NS16550=y
 CONFIG_SPI=y
-CONFIG_DM_SPI=y
 CONFIG_ATCSPI200_SPI=y
-CONFIG_TIMER=y
 CONFIG_ATCPIT100_TIMER=y