nb/intel/gm45: Call ddr3_calibrate_zq() only for DDR3 :)

Change-Id: I7d00ddf727e7250b767a1c4b58bf11b17e900fc1
Signed-off-by: Nico Huber <nico.h@gmx.de>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/34828
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/northbridge/intel/gm45/raminit.c

@@ -1799,7 +1799,8 @@ void raminit(sysinfo_t *const sysinfo, const int s3resume)
 
 
 	/* Perform ZQ calibration for DDR3. */
-	ddr3_calibrate_zq();
+	if (sysinfo->spd_type == DDR3)
+		ddr3_calibrate_zq();
 
 	/* Perform receive-enable calibration. */
 	raminit_receive_enable_calibration(timings, dimms);