[SYCL][NFC] Remove a compilation warning with GCC 8.2.0

Parenthesize the boolean comparisons a little bit more to clarify
understanding.

Signed-off-by: Ronan Keryell <[email protected]>

Author: keryell

clang/lib/Frontend/CompilerInvocation.cpp

@@ -122,8 +122,8 @@ CompilerInvocationBase::~CompilerInvocationBase() = default;
 static unsigned getOptimizationLevel(ArgList &Args, InputKind IK,
                                      DiagnosticsEngine &Diags) {
   unsigned DefaultOpt = llvm::CodeGenOpt::None;
-  if (IK.getLanguage() == InputKind::OpenCL &&
-      !Args.hasArg(OPT_cl_opt_disable) || Args.hasArg(OPT_fsycl_is_device))
+  if ((IK.getLanguage() == InputKind::OpenCL &&
+      !Args.hasArg(OPT_cl_opt_disable)) || Args.hasArg(OPT_fsycl_is_device))
     DefaultOpt = llvm::CodeGenOpt::Default;
 
   if (Arg *A = Args.getLastArg(options::OPT_O_Group)) {