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/a4m072_defconfig b/configs/a4m072_defconfig
index 0054d4c..4fbffb6 100644
--- a/configs/a4m072_defconfig
+++ b/configs/a4m072_defconfig
@@ -7,6 +7,7 @@
 CONFIG_AUTOBOOT_KEYED=y
 CONFIG_AUTOBOOT_PROMPT="autoboot in %d seconds\n"
 CONFIG_AUTOBOOT_DELAY_STR="asdfg"
+CONFIG_CMD_IDE=y
 CONFIG_CMD_USB=y
 # CONFIG_CMD_SETEXPR is not set
 CONFIG_CMD_DHCP=y