uart8250: Drop includes in superio

Change-Id: If723896cc31da75dbb3a63d5dc959764e96fded1
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-on: http://review.coreboot.org/5139
Tested-by: build bot (Jenkins)
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-by: Alexandru Gagniuc <mr.nuke.me@gmail.com>

src/superio/intel/i3100/superio.c

@@ -21,7 +21,6 @@
 #include <stdlib.h>
 #include <device/device.h>
 #include <device/pnp.h>
-#include <uart8250.h>
 #include "i3100.h"
 #include <arch/io.h>