reset: Provide new single-function reset API

board_reset() replaces the existing common reset API. There is no common
distinction between reset types across platforms, hence, common code
could never decide which one to call.

Currently only hard_reset() is used by common code. We replace these
calls and provide a fall-back to the current hard_reset() implemen-
tation. The fall-back will be removed along with hard_reset() after the
transition of all boards.

Change-Id: I274a8cee9cb38226b5a0bdff6a847c74ef0b3128
Signed-off-by: Nico Huber <nico.h@gmx.de>
Reviewed-on: https://review.coreboot.org/29047
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Julius Werner <jwerner@chromium.org>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>

src/lib/prog_loaders.c

@@ -84,8 +84,7 @@ static void ramstage_cache_invalid(void)
 {
 	printk(BIOS_ERR, "ramstage cache invalid.\n");
 	if (IS_ENABLED(CONFIG_RESET_ON_INVALID_RAMSTAGE_CACHE)) {
-		hard_reset();
-		halt();
+		board_reset();
 	}
 }