pan/bi: Assume future Valhall is 16-wide warps

This is true for v10 at least, per the public data sheet. It seems like a
reasonable default going forward to eliminate a special case.

Signed-off-by: Alyssa Rosenzweig <alyssa@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/14726>

src/panfrost/bifrost/bi_quirks.h

@@ -64,8 +64,7 @@ bifrost_lanes_per_warp(unsigned product_id)
         switch (product_id >> 12) {
         case 6: return 4;
         case 7: return 8;
-        case 9: return 16;
-        default: unreachable("Invalid Bifrost/Valhall GPU major");
+        default: return 16;
         }
 }