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/cmd/Kconfig b/cmd/Kconfig
index 1e3cd02..2c89a77 100644
--- a/cmd/Kconfig
+++ b/cmd/Kconfig
@@ -484,6 +484,14 @@
 	  option is to use sandbox and pass the -d point to sandbox's
 	  u-boot.dtb file.
 
+config CMD_IDE
+	bool "ide - Support for IDE drivers"
+	help
+	  Provides an 'ide' command which allows accessing the IDE drive,
+	  reseting the IDE interface, printing the partition table and
+	  geting device info. It also enables the 'diskboot' command which
+	  permits booting from an IDE drive.
+
 config CMD_LOADB
 	bool "loadb"
 	default y