broadcom/simulator: handle DRM_V3D_PARAM_SUPPORTS_MULTISYNC_EXT

Without this the simulator wrapper will abort upon seeing this
query, rendering the driver unusable in that context.

Also, it seems the simulator environment doesn't quite work with
multisync at present, so do not enable it until we figure out what
the issue is.

Reviewed-by: Melissa Wen <mwen@igalia.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/14678>

src/broadcom/simulator/v3dx_simulator.c

@@ -269,6 +269,9 @@ v3dX(simulator_get_param_ioctl)(struct v3d_hw *v3d,
         case DRM_V3D_PARAM_SUPPORTS_PERFMON:
                 args->value = V3D_VERSION >= 41;
                 return 0;
+        case DRM_V3D_PARAM_SUPPORTS_MULTISYNC_EXT:
+                args->value = 0;
+                return 0;
         }
 
         if (args->param < ARRAY_SIZE(reg_map) && reg_map[args->param]) {