VAAPI: Check libva version to make 4K working again

This checks for version >= 0.34 and allows decoding of surfaces larger than 1080p again on supported libva version. [s]If we can avoid the additional call to vaInitiliaze I would be happy, but I did not find a simple solution that early in the chain.[/s]

@elupus @btbn if you see a nicer solution let me know