[ROCm] temporary workaround till __double2half support enabled in HIP (#3236)

* temporary WAR workaround till __double2half support enabled in HIP

* workaround only for hipcc

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Co-authored-by: NLogan Adams <114770087+loadams@users.noreply.github.com>

csrc/includes/conversion_utils.h

@@ -266,7 +266,12 @@ DS_D_INLINE float2 to(__nv_bfloat162 val)
 template <>
 DS_D_INLINE __half to(double val)
 {
+#ifdef __HIP_PLATFORM_HCC__
+    float val_f = __double2float_rn(val);
+    return __float2half(val_f);
+#else
     return __double2half(val);
+#endif
 }
 template <>
 DS_D_INLINE __half to(float val)