zink: more accurately check samplecount caps for shader images

lavapipe can only do up to 4bits, so this isn't just a binary check

Fixes: 0daa61553d ("zink: check if multisample support exists for shader image formats")

Reviewed-by: Erik Faye-Lund <erik.faye-lund@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/9713>

src/gallium/drivers/zink/zink_screen.c

@@ -796,7 +796,7 @@ zink_is_format_supported(struct pipe_screen *pscreen,
             return false;
       }
       if (bind & PIPE_BIND_SHADER_IMAGE) {
-          if (!screen->info.feats.features.shaderStorageImageMultisample)
+          if (!(screen->info.props.limits.storageImageSampleCounts & sample_mask))
              return false;
       }
    }