fix opencl winograd fp16 bug

mindspore/lite/src/runtime/kernel/opencl/cl/winograd.cl

@@ -52,6 +52,10 @@ __kernel void Winograd4x4To36(__read_only image2d_t input,    // height=N*H
     for (int x = 0; x < 6; x++) {
       acc += BtD_row[x] * Bt[y * 6 + x];
     }
+#if FP16_ENABLE
+    acc = min(acc, HALF_MAX);
+    acc = max(acc, -HALF_MAX);
+#endif
     WRITE_IMAGE(output, (int2)(tile_hw, y_idx + y), acc);
   }
 }

mindspore/lite/src/runtime/opencl/opencl_runtime.cc

@@ -367,12 +367,12 @@ int OpenCLRuntime::BuildKernel(cl::Kernel &kernel, const std::string &program_na
   std::string build_option = default_build_option_;
   if (fp16_enable_) {
     build_option +=
-      " -DFLT=half -DFLT4=half4 -DFLT16=half16 -DAS_FLT4=as_half4 -DAS_UINT4=as_ushort4 -DUINT4=ushort4 "
-      "-DWRITE_IMAGE=write_imageh -DREAD_IMAGE=read_imageh -DTO_FLT=convert_half -DTO_FLT4=convert_half4";
+      " -DFP16_ENABLE=1 -DFLT=half -DFLT4=half4 -DFLT16=half16 -DAS_FLT4=as_half4 -DAS_UINT4=as_ushort4 -DUINT4=ushort4"
+      " -DWRITE_IMAGE=write_imageh -DREAD_IMAGE=read_imageh -DTO_FLT=convert_half -DTO_FLT4=convert_half4";
   } else {
     build_option +=
-      " -DFLT=float -DFLT4=float4 -DFLT16=float16 -DAS_FLT4=as_float4 -DAS_UINT4=as_uint4 -DUINT4=uint4 "
-      "-DWRITE_IMAGE=write_imagef -DREAD_IMAGE=read_imagef -DTO_FLT=convert_float -DTO_FLT4=convert_float4";
+      " -DFP16_ENABLE=0 -DFLT=float -DFLT4=float4 -DFLT16=float16 -DAS_FLT4=as_float4 -DAS_UINT4=as_uint4 -DUINT4=uint4"
+      " -DWRITE_IMAGE=write_imagef -DREAD_IMAGE=read_imagef -DTO_FLT=convert_float -DTO_FLT4=convert_float4";
   }
   build_option =
     std::accumulate(build_options_ext.begin(), build_options_ext.end(), build_option,