Free xcb_intern_atom_reply_t* in linux platform

[caiovpsilveira]

https://github.com/travisvroman/kohi/blob/e529fd20a81d8b55c24a77635b815b0875eb810f/engine/src/platform/platform_linux.c#L276

Running with valgrind reports a leak caused by this. Checking the xcb header comment, it states that this should be freed by the caller.