nb/intel/x4x: Place raminit definitions in raminit.h

There's no need to have implementation details in a public header.

Tested with BUILD_TIMELESS=1, Asus P5QL PRO remains identical.

Change-Id: I04d8c610d3e52adecfe96cc435f0523bedf3060a
Signed-off-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/45424
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Patrick Rudolph <siro@das-labor.org>

src/northbridge/intel/x4x/raminit.c

@@ -14,6 +14,7 @@
 #include <timestamp.h>
 #include <types.h>
 
+#include "raminit.h"
 #include "x4x.h"
 
 #define MRC_CACHE_VERSION 0