syscalls2 x64 and ARM64 do not support 32-bit syscalls

[lacraig2]

This seems to have been a deliberate choice. I'd like to know if anyone has strong feelings about it.

If not, I'd propose we add support for it.

If people do care about it I think it'd be fine to add an argument to syscalls2 for one functionality or the other.

@LauraLMann it looks like git blame has you adding this so I want to make sure to get your input.

https://github.com/panda-re/panda/blob/1b4c51b32284bf894ad2fe941f166424edb60df0/panda/plugins/syscalls2/syscalls2.cpp#L1044-L1059