llama: Include algorithm header needed for C++23

[cpeterso]

llama-hparams.cpp currently depends on the <algorithm> header being indirectly included by another std header. When compiling with -std=c++23, clang defines _LIBCPP_REMOVE_TRANSITIVE_INCLUDES [1] and libc++ std headers will include fewer other std headers indirectly. So include <algorithm> where it's needed.

[1] https://libcxx.llvm.org/DesignDocs/HeaderRemovalPolicy.html

I see this error when building llama.cpp as part of Firefox with -std=c++23:

llama.cpp/src/llama-hparams.cpp:99:20: error: no member named 'max' in namespace 'std'
99 | val = std::max(val, n_embd_k_gqa(il));
| ~~~~~^
llama.cpp/src/llama-hparams.cpp:108:20: error: no member named 'max' in namespace 'std'
108 | val = std::max(val, n_embd_v_gqa(il));
| ~~~~~^