common, autoboot: sync functionality with Kconfig description

add back again special case: -2
autoboot with no delay and no check for abort

as described in Kconfig option, see common/Kconfig
help text for option BOOTDELAY.
Signed-off-by: NHeiko Schocher <hs@denx.de>
Reviewed-by: NTom Rini <trini@konsulko.com>
Reviewed-by: NSimon Glass <sjg@chromium.org>

common/autoboot.c

@@ -363,7 +363,8 @@ void autoboot_command(const char *s)
 {
 	debug("### main_loop: bootcmd=\"%s\"\n", s ? s : "<UNDEFINED>");
 
-	if (stored_bootdelay != -1 && s && !abortboot(stored_bootdelay)) {
+	if (s && (stored_bootdelay == -2 ||
+		 (stored_bootdelay != -1 && !abortboot(stored_bootdelay)))) {
 		bool lock;
 		int prev;