meson: don't generate file into subdirs

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

Fixes: 5adfc860
       ("lima/ppir: move sin/cos input scaling into NIR")
Reviewed-by: Vasily Khoruzhick <anarsoul@gmail.com>
22 jobs for !1926 with meson-lima-dont-generate-into-subdir in 4 minutes and 32 seconds (queued for 14 seconds)
merge request