[SYCL] float_to_int8_rn function

I have a question. Is there a function for rounding to nearest integer with saturation in SYCL ? Thanks.

```
/*
* Copyright (c) 2019-2023, NVIDIA CORPORATION. All rights reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/

static inline __device__ char float_to_int8_rn(float x)
{
uint dst;
asm volatile("cvt.rni.sat.s8.f32 %0, %1;" : "=r"(dst) : "f"(x));
return reinterpret_cast(dst);
}
```