When I ported from libdrm, I forgot to add the line to reset
the sem, we just need to reset the context.
This fixes a regression in DOOM.
Fixes: 9ac1432a571 ("radv: port to new libdrm API.") Reported-by: Grazvydas Ignotas <notasas@gmail.com> Signed-off-by: Dave Airlie <airlied@redhat.com>