nb/intel/x4x: Fix P45 CAPID max frequency

It looks like on the ASUS P5QC has 0 in this CAPID field while still supporting
TCK_666MHZ.

Change-Id: Id1a94d91434dbe782fcc56dad56fcaee4e78463b
Signed-off-by: Arthur Heymans <arthur@aheymans.xyz>
Reviewed-on: https://review.coreboot.org/29101
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Felix Held <felix-coreboot@felixheld.de>

src/northbridge/intel/x4x/raminit.c

@@ -296,6 +296,7 @@ static void select_cas_dramfreq_ddr3(struct sysinfo *s,
 		min_tCLK = MAX(min_tCLK, TCK_533MHZ);
 		break;
 	case 3: /* Only on P45 */
+	case 0:
 		min_tCLK = MAX(min_tCLK, TCK_666MHZ);
 		break;
 	}