Fix test cxx-call-kernel.cpp

Only test it with x86 since other target may have an ABI
making it difficult to test.

Change-Id: I85423c8bbbbbb8f24cb3ea4cb64a408069b4d61c

Author: yxsamliu

clang/test/CodeGenCUDA/cxx-call-kernel.cpp

@@ -1,5 +1,8 @@
-// RUN: %clang_cc1 -x hip -emit-llvm-bc %s -o %t.hip.bc
-// RUN: %clang_cc1 -mlink-bitcode-file %t.hip.bc -DHIP_PLATFORM -emit-llvm \
+// REQUIRES: x86-registered-target
+// RUN: %clang_cc1 -triple x86_64-unknown-linux-gnu \
+// RUN:   -x hip -emit-llvm-bc %s -o %t.hip.bc
+// RUN: %clang_cc1 -triple x86_64-unknown-linux-gnu \
+// RUN:   -mlink-bitcode-file %t.hip.bc -DHIP_PLATFORM -emit-llvm \
 // RUN:   %s -o - | FileCheck %s
 
 #include "Inputs/cuda.h"