Let hipcc not pass -mllvm option to HIP-Clang on Windows (#1924)

Currently there is a clang bug on Windows causing duplicate -mllvm options in clang -cc1.

Tempoarily disable -mllvm options for HIP-Clang on Windows until the bug is fixed.

Change-Id: I3a4393ba7745989398dc6c6001722837dad18704

[ROCm/clr commit: 6b1956d139]

projects/clr/hipamd/bin/hipcc

@@ -711,7 +711,9 @@ if ($HIP_PLATFORM eq "clang") {
         $HIPCXXFLAGS .= " -O3";
         $HIPLDFLAGS .= " -O3";
     }
-    if ($optArg ne "-O0") {
+    # Do not pass -mllvm on Windows since there is a clang bug causing duplicate -mllvm options in clang -cc1 on Windows.
+    # ToDo : remove restriction for Windows after clang bug is fixed.
+    if ($optArg ne "-O0" and not $isWindows) {
         $HIPCXXFLAGS .= " -mllvm -amdgpu-early-inline-all=true -mllvm -amdgpu-function-calls=false";
         if ($needLDFLAGS and not $needCXXFLAGS) {
             $HIPLDFLAGS .= " -mllvm -amdgpu-early-inline-all=true -mllvm -amdgpu-function-calls=false";