x86, mce: Check the result of ancient_init()

Because "ancient CPUs" like p5 and winchip don't have X86_FEATURE_MCA
(I suppose so), mcheck_cpu_init() on such CPUs will return at check of
mce_available() after __mcheck_cpu_ancient_init().

It is hard to know this implicit behavior without knowing the CPUs
well. So make it clear that we leave mcheck_cpu_init() when the CPU is
initialized in __mcheck_cpu_ancient_init().

Signed-off-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Acked-by: Tony Luck <tony.luck@intel.com>
Link: http://lkml.kernel.org/r/4DEED74B.20502@jp.fujitsu.com
Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>

arch/x86/kernel/cpu/mcheck/mce.c

@@ -1332,18 +1332,23 @@ static int __cpuinit __mcheck_cpu_apply_quirks(struct cpuinfo_x86 *c)
 	return 0;
 }
 
-static void __cpuinit __mcheck_cpu_ancient_init(struct cpuinfo_x86 *c)
+static int __cpuinit __mcheck_cpu_ancient_init(struct cpuinfo_x86 *c)
 {
 	if (c->x86 != 5)
-		return;
+		return 0;
+
 	switch (c->x86_vendor) {
 	case X86_VENDOR_INTEL:
 		intel_p5_mcheck_init(c);
+		return 1;
 		break;
 	case X86_VENDOR_CENTAUR:
 		winchip_mcheck_init(c);
+		return 1;
 		break;
 	}
+
+	return 0;
 }
 
 static void __mcheck_cpu_init_vendor(struct cpuinfo_x86 *c)
@@ -1397,7 +1402,8 @@ void __cpuinit mcheck_cpu_init(struct cpuinfo_x86 *c)
 	if (mce_disabled)
 		return;
 
-	__mcheck_cpu_ancient_init(c);
+	if (__mcheck_cpu_ancient_init(c))
+		return;
 
 	if (!mce_available(c))
 		return;