egl: disable partial redraw when gallium hud is active

egl: disable partial redraw when gallium hud is active

We draw the gallium hud directly to the rendered buffer, meaning that if
the buffer age is queried and then a partial redraw is done, we get a
ghosting effect from the hud drawn in previous frames.

Since we need to draw the hud with updated values every frame anyway,
there's no harm in disabling the buffer age and partial redraw.

Signed-off-by: Italo Nicola <italonicola@collabora.com>
Reviewed-by: Eric Engestrom <eric@engestrom.ch>
Tested-by: Chris Healy <cphealy@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/20387>