[Cin] av1 hw decoding

[Andrea paz]

Your patch doesn't seem to work: the message still appears that
'libdav1d does not support
vaap'i. You can't see any load on the GPU. It is the same starting CinGG with
“CIN_HW_DEV=vaapi” than without.

I have tried various appimages:
- kdenlive has the option for GPU disabled (I think I need to install motif).
- Openshot doesn't start because it requires glibc 2.35 while I have 2.39.
- Shotcut works: GPU = 10-30%; CPU = 10-30%. However, it indicates
that it is using
libdav1d for the decoding and I don't understand why it works.