gallium: add PIPE_CAP_ALLOW_DYNAMIC_VAO_FASTPATH

Fixes: 42842306d3 ("mesa,st/mesa: add a fast path for non-static VAOs")
Signed-off-by: Marcin Ślusarz <marcin.slusarz@intel.com>
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/9857>

src/gallium/auxiliary/util/u_screen.c

@@ -462,6 +462,9 @@ u_pipe_screen_get_param_defaults(struct pipe_screen *pscreen,
    case PIPE_CAP_SAMPLER_REDUCTION_MINMAX:
       return 0;
 
+   case PIPE_CAP_ALLOW_DYNAMIC_VAO_FASTPATH:
+      return 1;
+
    default:
       unreachable("bad PIPE_CAP_*");
    }

src/gallium/include/pipe/p_defines.h

@@ -986,6 +986,7 @@ enum pipe_cap
    PIPE_CAP_GL_CLAMP,
    PIPE_CAP_TEXRECT,
    PIPE_CAP_SAMPLER_REDUCTION_MINMAX,
+   PIPE_CAP_ALLOW_DYNAMIC_VAO_FASTPATH,
 
    PIPE_CAP_LAST,
    /* XXX do not add caps after PIPE_CAP_LAST! */

src/mesa/state_tracker/st_extensions.c

@@ -610,7 +610,8 @@ void st_init_limits(struct pipe_screen *screen,
       screen->get_param(screen, PIPE_CAP_SIGNED_VERTEX_BUFFER_OFFSET);
 
    c->MultiDrawWithUserIndices = true;
-   c->AllowDynamicVAOFastPath = true;
+   c->AllowDynamicVAOFastPath =
+         screen->get_param(screen, PIPE_CAP_ALLOW_DYNAMIC_VAO_FASTPATH);
 
    c->glBeginEndBufferSize =
       screen->get_param(screen, PIPE_CAP_GL_BEGIN_END_BUFFER_SIZE);