Convert CONFIG_CMD_KGDB to Kconfig

This converts the following to Kconfig:
   CONFIG_CMD_KGDB

Signed-off-by: Simon Glass <sjg@chromium.org>

README

@@ -853,7 +853,6 @@ The following options need to be configured:
 		CONFIG_CMD_IMPORTENV	* import an environment
 		CONFIG_CMD_INI		* import data from an ini file into the env
 		CONFIG_CMD_ITEST	  Integer/string test of 2 values
-		CONFIG_CMD_KGDB		* kgdb
 		CONFIG_CMD_LDRINFO	* ldrinfo (display Blackfin loader)
 		CONFIG_CMD_LINK_LOCAL	* link-local IP address auto-configuration
 					  (169.254.*.*)

cmd/Kconfig

@@ -1200,6 +1200,15 @@ config CMD_IRQ
 
 	     interrupts - enable or disable interrupts
 	     irqinfo - print device-specific interrupt information
+
+config CMD_KGDB
+	bool "kgdb - Allow debugging of U-Boot with gdb"
+	help
+	  This enables a 'kgdb' command which allows gdb to connect to U-Boot
+	  over a serial link for debugging purposes. This allows
+	  single-stepping, inspecting variables, etc. This is supported only
+	  on PowerPC at present.
+
 endmenu
 
 config CMD_UBI

include/config_cmd_all.h

@@ -13,7 +13,6 @@
  * Alphabetical list of all possible commands.
  */
 
-#define CONFIG_CMD_KGDB		/* kgdb				*/
 #define CONFIG_CMD_MFSL		/* FSL support for Microblaze	*/
 #define CONFIG_CMD_MTDPARTS	/* mtd parts support		*/
 #define CONFIG_CMD_NAND		/* NAND support			*/

scripts/config_whitelist.txt

@@ -383,7 +383,6 @@ CONFIG_CM922T_XA10
 CONFIG_CMDLINE_EDITING
 CONFIG_CMDLINE_PS_SUPPORT
 CONFIG_CMDLINE_TAG
-CONFIG_CMD_KGDB
 CONFIG_CMD_LOADY
 CONFIG_CMD_LZMADEC
 CONFIG_CMD_MAX6957