OpenCL: CL_INVALID_BUFFER_SIZE on RX 6700 XT 12GB with rusticl loader
**Describe the bug**
```
[2023-09-19 23:08:27.682]  opencl   error CL_INVALID_BUFFER_SIZE when calling clCreateBuffer with buffer size 2181038080
```
Looking at other issues, this is usually the case when there is not enough VRAM, but I have 12GB so that shouldn't be the problem. It's possible that the Mesa ICD is to blame and I should file a bug with mesa, but I need to investigate this further first.

**To Reproduce**
- Have a Navi 20 series card with enough VRAM
- Install mesa-opencl-icd (on Debian at least)
- Set the opencl platform config to `Mesa/X.org`
- Set cpu enabled to `false` debugging purposes
- Run `RUSTICL_ENABLE=radeonsi ./xmrig`

```
[2023-09-19 23:08:27.682]  opencl   error CL_INVALID_BUFFER_SIZE when calling clCreateBuffer with buffer size 2181038080
```

**Expected behavior**
It Just Werks™

**Required data**
 - [miner.log](https://github.com/xmrig/xmrig/files/12666815/miner.log)
 - [config.json](https://github.com/xmrig/xmrig/files/12666798/config.txt)
 - OS: Debian sid
 - GPU: AMD Radeon RX 6700 XT (navi22, LLVM 15.0.7, DRM 3.54, 6.5.0-1-rt-amd64)

**Additional context**
I managed to figure out how to get OpenCL working with the Mesa rusticl ICD, which is necessary since the old Mesa ICD doesn't support newer Navi cards. I had to set the platform parameters in the opencl part of the configuration to `Mesa/X.org` or I would get a `(selected OpenCL platform NOT found)` error. I also had to set the environment variable `RUSTICL_ENABLE=radeonsi`.