Update Kernel parameters for Fedora 43

[srom]

First off, amazing work mate! I've been able to run Qwen3-235b with 3 bit quantization out of the box using your llama-vulkan-radv toolbox. Hats off, this is incredibly useful.

I just noticed that on Fedora 43, the amggpu.gttsize kernel parameter is deprecated. A quick search pointed to other parameters: ttm.pages_limit and ttm.page_pool_size.

(Source: https://www.jeffgeerling.com/blog/2025/increasing-vram-allocation-on-amd-ai-apus-under-linux)

This PR adds a section for Fedora 43 on the README.md file.

I have tested the configuration on my Framework Desktop running Fedora 43 and it works wonder:

$ sudo dmesg | grep "amdgpu.*memory"
[    4.658377] amdgpu 0000:c2:00.0: amdgpu: amdgpu: 512M of VRAM memory ready
[    4.658384] amdgpu 0000:c2:00.0: amdgpu: amdgpu: 126976M of GTT memory ready.

Hope this helps!