runner.go: Remove unused arguments

Now that server.cpp is gone, we don't need to keep passing arguments
that were only ignored and only kept for compatibility.

docs/api.md

@@ -355,7 +355,6 @@ curl http://localhost:11434/api/generate -d '{
     "num_gpu": 1,
     "main_gpu": 0,
     "low_vram": false,
-    "f16_kv": true,
     "vocab_only": false,
     "use_mmap": true,
     "use_mlock": false,