Revert "nb/intel/gm45/gm45.h: Remove duplicated include"

This reverts commit 27af8a7e5d.

Reason for revert: This depends on CB:45517 which hasn't landed yet.

Change-Id: I2a6fbf54cfe01bf25e9ea8da84f6f2a17418f0ae
Reviewed-on: https://review.coreboot.org/c/coreboot/+/49647
Tested-by: Patrick Georgi <pgeorgi@google.com>
Reviewed-by: Patrick Georgi <pgeorgi@google.com>

src/northbridge/intel/gm45/gm45.h

@@ -164,6 +164,8 @@ enum {
 #define CMOS_READ_TRAINING	0x80 /* 16 bytes */
 #define CMOS_WRITE_TRAINING	0x90 /* 16 bytes (could be reduced to 10 bytes) */
 
+#include "memmap.h"
+
 /*
  * D0:F0
  */