bootmenu: U-Boot console is enabled as default

The commit 2158b0da220c ("bootmenu: add Kconfig option
not to enter U-Boot console") disables to enter U-Boot
console from bootmenu as default, this change affects the
existing bootmenu users.

This commit reverts the default behavior, the bootmenu can
enter U-Boot console same as before.
CMD_BOOTMENU_ENTER_UBOOT_CONSOLE is renamed
BOOTMENU_DISABLE_UBOOT_CONSOLE and depends on
AUTOBOOT_MENU_SHOW.

Fixes: 2158b0da220c ("bootmenu: add Kconfig option not to enter U-Boot console")
Signed-off-by: Masahisa Kojima <masahisa.kojima@linaro.org>
Tested-by: Pali Rohar <pali@kernel.org>
Reviewed-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Reviewed-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
diff --git a/boot/Kconfig b/boot/Kconfig
index dff4d23..08451c6 100644
--- a/boot/Kconfig
+++ b/boot/Kconfig
@@ -1143,6 +1143,13 @@
 	  environmnent variable (if enabled) and before handling the boot delay.
 	  See README.bootmenu for more details.
 
+config BOOTMENU_DISABLE_UBOOT_CONSOLE
+	bool "Disallow bootmenu to enter the U-Boot console"
+	depends on AUTOBOOT_MENU_SHOW
+	help
+	  If this option is enabled, user can not enter the U-Boot console from
+	  bootmenu. It increases the system security.
+
 config BOOT_RETRY
 	bool "Boot retry feature"
 	help