autoboot.c: Move config options to Kconfig

autoboot.c: Move config options to Kconfig

This patch moves the following config options to Kconfig:

CONFIG_AUTOBOOT_KEYED
CONFIG_AUTOBOOT_PROMPT
CONFIG_AUTOBOOT_DELAY_STR
CONFIG_AUTOBOOT_STOP_STR
AUTOBOOT_KEYED_CTRLC

Signed-off-by: Stefan Roese <sr@denx.de>
Reviewed-by: Simon Glass <sjg@chromium.org>
[trini: Drop ip04 and pm9263 configs/ additions, those boards previously
 set CONFIG_AUTOBOOT_PROMPT but never used it, re-run savedefconfig over
 all boards that did change. Make digsy_mtc_* string include seconds to
 match others and not warn. ]
Signed-off-by: Tom Rini <trini@konsulko.com>
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>