Enable intel_ocl_bicc for x86_64 target only. Remove fix from 171969 that enabled this extension for multiple targets.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@172052 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Basic/Targets.cpp b/lib/Basic/Targets.cpp
index f79aec3..3426262 100644
--- a/lib/Basic/Targets.cpp
+++ b/lib/Basic/Targets.cpp
@@ -2895,7 +2895,9 @@
   }
 
   virtual CallingConvCheckResult checkCallingConvention(CallingConv CC) const {
-    return TargetInfo::checkCallingConvention(CC);
+    return (CC == CC_Default ||
+            CC == CC_C || 
+            CC == CC_IntelOclBicc) ? CCCR_OK : CCCR_Warning;
   }
 
   virtual CallingConv getDefaultCallingConv(CallingConvMethodType MT) const {