Convert CONFIG_CMD_ZBOOT to Kconfig

This converts the following to Kconfig:
   CONFIG_CMD_ZBOOT

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>

arch/Kconfig

@@ -113,6 +113,7 @@ config X86
 	imply CMD_IO
 	imply CMD_IRQ
 	imply CMD_SF_TEST
+	imply CMD_ZBOOT
 
 config XTENSA
 	bool "Xtensa architecture"

cmd/Kconfig

@@ -312,6 +312,18 @@ config CMD_THOR_DOWNLOAD
 	  There is no documentation about this within the U-Boot source code
 	  but you should be able to find something on the interwebs.
 
+config CMD_ZBOOT
+	bool "zboot - x86 boot command"
+	help
+	  With x86 machines it is common to boot a bzImage file which
+	  contains both a kernel and a setup.bin file. The latter includes
+	  configuration information from the dark ages which x86 boards still
+	  need to pick things out of.
+
+	  Consider using FIT in preference to this since it supports directly
+	  booting both 32- and 64-bit kernels, as well as secure boot.
+	  Documentation is available in doc/uImage.FIT/x86-fit-boot.txt
+
 endmenu
 
 menu "Environment commands"

include/configs/edison.h

@@ -10,7 +10,6 @@
 #include <asm/ibmpc.h>
 
 /* Boot */
-#define CONFIG_CMD_ZBOOT
 #define CONFIG_BOOTCOMMAND "run bootcmd"
 
 /* DISK Partition support */

include/configs/x86-common.h

@@ -67,8 +67,6 @@
  * Command line configuration.
  */
 
-#define CONFIG_CMD_ZBOOT
-
 #define CONFIG_BOOTARGS		\
 	"root=/dev/sdb3 init=/sbin/init rootwait ro"
 #define CONFIG_BOOTCOMMAND	\

scripts/config_whitelist.txt

@@ -293,7 +293,6 @@ CONFIG_CM922T_XA10
 CONFIG_CMDLINE_EDITING
 CONFIG_CMDLINE_PS_SUPPORT
 CONFIG_CMDLINE_TAG
-CONFIG_CMD_ZBOOT
 CONFIG_CMD_ZFS
 CONFIG_CM_INIT
 CONFIG_CM_MULTIPLE_SSRAM