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

Change-Id: I03461cb9e87b4ddd599e5601637a75b012694e7c
Signed-off-by: Elyes HAOUAS <ehaouas@noos.fr>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/36047
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Felix Held <felix-coreboot@felixheld.de>

src/mainboard/kontron/986lcd-m/mainboard.c

@@ -20,7 +20,6 @@
 #include <console/console.h>
 #include <drivers/intel/gma/int15.h>
 #include <pc80/mc146818rtc.h>
-#include <arch/io.h>
 #include <superio/hwm5_conf.h>
 
 /* Hardware Monitor */