use the platform api to decide the specific instruction support or not

test=develop

paddle/fluid/operators/elementwise/elementwise_mul_mkldnn_op.cc

@@ -83,12 +83,7 @@ class ElementwiseMulMKLDNNKernel : public framework::OpKernel<T> {
     UpdateDataFormat(ctx, const_cast<Tensor*>(x), "x_data_format");
     UpdateDataFormat(ctx, const_cast<Tensor*>(y), "y_data_format");
 
-#ifdef PADDLE_WITH_XBYAK
-    Xbyak::util::Cpu cpu;
-    const bool is_avx512_enabled = cpu.has(Xbyak::util::Cpu::tAVX512F);
-#else
     const bool is_avx512_enabled = platform::MayIUse(platform::avx512f);
-#endif  // PADDLE_WITH_XBYAK
     const bool are_dims_divisable = !(x_int_dims[1] % 16);
     const bool is_x_format_correct = x->format() == memory::format::nChw16c;
     const bool is_y_format_correct = y->format() == memory::format::nc;