configs: add DM_SPI config option

This patch adds CONFIG_DM_SPI for all m68k boards using
the cf_spi.c driver (DSPI module).

Reviewed-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Angelo Dureghello <angelo@sysam.it>
diff --git a/configs/M52277EVB_stmicro_defconfig b/configs/M52277EVB_stmicro_defconfig
index 84733f6..d417be6 100644
--- a/configs/M52277EVB_stmicro_defconfig
+++ b/configs/M52277EVB_stmicro_defconfig
@@ -27,4 +27,5 @@
 CONFIG_SPI_FLASH=y
 CONFIG_SPI_FLASH_STMICRO=y
 CONFIG_SPI=y
+CONFIG_DM_SPI=y
 CONFIG_CF_SPI=y