nouveau/video: properly detect the decoder class for availability checks

nouveau/video: properly detect the decoder class for availability checks

The kernel is now more strict with the class ids it exposes, so we need
to check the G98 and MCP89 classes as well as the GT215 class. This
effectively caused us to decide there were no decoding capabilities on
newer kernel for VP3 chips.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=95251
Signed-off-by: Ilia Mirkin <imirkin@alum.mit.edu>
Cc: "11.2" <mesa-stable@lists.freedesktop.org>