This seems to be a more official, common, simple way to check if the CPU is dual core or
single core.

Signed-off-by: Zheng Bao <zheng.bao@amd.com>

Index: src/southbridge/amd/sb600/sb600_early_setup.c
===================================================================
--- src/southbridge/amd/sb600/sb600_early_setup.c	(revision 4413)
+++ src/southbridge/amd/sb600/sb600_early_setup.c	(working copy)
@@ -125,11 +125,7 @@
 
 static u8 dual_core()
 {
-	if(((cpuid_eax(0x80000000) & ~0xff) >= 8)) {
-		if(cpuid_ecx(0x80000008) & 1)
-			return 1;
-	}
-	return 0;
+	return (pci_read_config32(PCI_DEV(0, 0x18, 3), 0xE8) & (0x3<<12)) != 0;
 }
 
 /*