radv: add a workaround for a VGT hang with prim restart and strips

Otherwise, Yakuza and The Evil Within hang the GPU with DXVK.
This apparently only works on Polaris.

Suggested by Marek.

Cc: mesa-stable@lists.freedesktop.org
Signed-off-by: Samuel Pitoiset <samuel.pitoiset@gmail.com>
Reviewed-by: Bas Nieuwenhuizen <bas@basnieuwenhuizen.nl>
(cherry picked from commit d179312b)