msrtool: use a bit more clever cpuid vendor match

Not everything non-intel is AMD.

Change-Id: I06d6fbaa0b4f2c9e61d9b3b4aeeb349a91aa090e
Signed-off-by: Lubomir Rintel <lkundrak@v3.sk>
Reviewed-on: https://review.coreboot.org/18255
Reviewed-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

util/msrtool/msrtool.h

@@ -95,8 +95,8 @@ struct msrdef {
 #define MAX_CORES 8
 
 typedef enum {
-	VENDOR_INTEL = 1,
-	VENDOR_AMD = 2,
+	VENDOR_INTEL = 0x756e6547,
+	VENDOR_AMD = 0x68747541,
 } vendor_t;
 
 struct cpuid_t {