Fix indirect include for endianess

The function (preprocessor macro) we need is defined
in <endian.h> not <swab.h>.

Change-Id: I3a86c7050bf853e3a56a15421132240e19f40912
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-on: https://review.coreboot.org/c/31704
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/ec/google/wilco/bootblock.c

@@ -14,8 +14,8 @@
  */
 
 #include <arch/io.h>
+#include <endian.h>
 #include <device/pnp_def.h>
-#include <swab.h>
 
 #include "bootblock.h"
 

src/mainboard/emulation/qemu-i440fx/fw_cfg.c

@@ -11,8 +11,8 @@
  * GNU General Public License for more details.
  */
 
+#include <endian.h>
 #include <string.h>
-#include <swab.h>
 #include <smbios.h>
 #include <console/console.h>
 #include <arch/io.h>