asahi: Disable fp16 for browsers
What does this MR do and why?
Add the necessary scaffolding to support driconf options in asahi, and then disable fp16 support for all browsers.
There are way too many broken WebGL apps using the wrong precision qualifiers, which causes anything from jittery geometry to complete breakage (e.g. QuakeJS and other games).
In addition, a Firefox bug is breaking basic canvas rendering for the same reason (mozilla bug #1845309).
Let's just disable fp16 for browsers. There is no hope of getting all this broken stuff fixed.
Signed-off-by: Asahi Lina lina@asahilina.net