meson: don't generate file into subdirs

This is unsupported by meson and may become a hard error in the future.

Fixes: 5adfc8602c639827af0ba9a1059bd165a3ae49e7
       ("lima/ppir: move sin/cos input scaling into NIR")
Reviewed-by: Vasily Khoruzhick <anarsoul@gmail.com>
1 file changed