src/sb: Fix non-local header treated as local

Remove some unneeded includes.

Change-Id: I4b9bcb74b6441db9e44fe471b9cd789e42e7093a
Signed-off-by: Elyes HAOUAS <ehaouas@noos.fr>
Reviewed-on: https://review.coreboot.org/27130
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Patrick Georgi <pgeorgi@google.com>

src/southbridge/intel/ibexpeak/smihandler.c

@@ -31,7 +31,7 @@
  *  1. the chipset can do it
  *  2. we don't need to worry about how we leave 0xcf8/0xcfc behind
  */
-#include "northbridge/intel/nehalem/nehalem.h"
+#include <northbridge/intel/nehalem/nehalem.h>
 #include <southbridge/intel/common/gpio.h>
 #include <arch/io.h>