Convert CONFIG_CMD_IDE to Kconfig

This converts the following to Kconfig:
   CONFIG_CMD_IDE

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/configs/ds109_defconfig b/configs/ds109_defconfig
index e9f67ae..46ac567 100644
--- a/configs/ds109_defconfig
+++ b/configs/ds109_defconfig
@@ -3,6 +3,7 @@
 CONFIG_TARGET_DS109=y
 CONFIG_HUSH_PARSER=y
 # CONFIG_CMD_IMLS is not set
+CONFIG_CMD_IDE=y
 # CONFIG_CMD_FLASH is not set
 CONFIG_CMD_SF=y
 CONFIG_CMD_I2C=y