common: bootdelay: move CONFIG_BOOTDELAY into a Kconfig option

move CONFIG_BOOTDELAY into a Kconfig option. Used for this
purpose the moveconfig.py tool in tools.

Signed-off-by: Heiko Schocher <hs@denx.de>

Reviewed-by: Tom Rini <trini@konsulko.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Igor Grinberg <grinberg@compulab.co.il>
diff --git a/configs/walnut_defconfig b/configs/walnut_defconfig
index 9fdb2b3..5f7b40d 100644
--- a/configs/walnut_defconfig
+++ b/configs/walnut_defconfig
@@ -2,6 +2,7 @@
 CONFIG_4xx=y
 CONFIG_TARGET_WALNUT=y
 CONFIG_OF_BOARD_SETUP=y
+CONFIG_BOOTDELAY=5
 CONFIG_HUSH_PARSER=y
 CONFIG_CMD_ASKENV=y
 CONFIG_CMD_GREPENV=y