treewide: Remove unused 'include <arch/io.h>'

Change-Id: I6f1d7625eb457084ba893b25518fdfdb59cf64db
Signed-off-by: Elyes Haouas <ehaouas@noos.fr>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/70693
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Kapil Porwal <kapilporwal@google.com>
Reviewed-by: Kyösti Mälkki <kyosti.malkki@gmail.com>

src/ec/kontron/kempld/kempld_gpio.c

@@ -1,7 +1,6 @@
 /* SPDX-License-Identifier: GPL-2.0-only */
 
 #include <stdint.h>
-#include <arch/io.h>
 
 #include "chip.h"
 #include "kempld.h"