!12660 fix gpu bceloss bug

From: @huaweib
Reviewed-by: @zhoufeng54,@chujinjin
Signed-off-by: @chujinjin

mindspore/ccsrc/backend/kernel_compiler/gpu/nn/binary_cross_entropy_gpu_kernel.h

@@ -59,7 +59,7 @@ class BinaryCrossEntropyGpuKernel : public GpuKernel {
       reduction_ = 2;
     }
     workspace_size_ = sizeof(T);
-    if (reduction_ == 0) {
+    if (reduction_ != 0) {
       workspace_size_ *= input_size_;
     }
     InitSizeLists();