[ARM64] Add arm64_be where it was accidentally missed from a bunch of if-conditions.

I think this is the last commit for ARM64 big endian in clang. This commit makes
arm_neon.h compile correctly.

llvm-svn: 207624
diff --git a/clang/lib/Sema/SemaChecking.cpp b/clang/lib/Sema/SemaChecking.cpp
index 6c84b97..526f891 100644
--- a/clang/lib/Sema/SemaChecking.cpp
+++ b/clang/lib/Sema/SemaChecking.cpp
@@ -310,6 +310,7 @@
           return ExprError();
         break;
       case llvm::Triple::arm64:
+      case llvm::Triple::arm64_be:
         if (CheckARM64BuiltinFunctionCall(BuiltinID, TheCall))
           return ExprError();
         break;