[X86] Correct the BDVER4 model numbers to include 0x70-0x7f.

According to wikipedia and some other googling suggests these should also be considered as BDVER4.

llvm-svn: 307466
diff --git a/llvm/lib/Support/Host.cpp b/llvm/lib/Support/Host.cpp
index 42b71ad..a552a1e 100644
--- a/llvm/lib/Support/Host.cpp
+++ b/llvm/lib/Support/Host.cpp
@@ -915,7 +915,7 @@
       *Subtype = AMD_BTVER1;
       break; // "btver1"
     }
-    if (Model >= 0x50 && Model <= 0x6f) {
+    if (Model >= 0x60 && Model <= 0x7f) {
       *Subtype = AMDFAM15H_BDVER4;
       break; // "bdver4"; 50h-6Fh: Excavator
     }