pan/texture: Correctly handle slice stride for MSAA

Currently, we will always be setting the slice stride in the plane
descriptor to the surface stride, as the check for multisampling is true
even for single sampled surfaces.

This change fixes this check.

Fixes: db20152c8a ("panfrost: Handle Valhall texturing")
Reviewed-by: Boris Brezillon <boris.brezillon@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/34839>

src/panfrost/lib/pan_texture.c

@@ -435,7 +435,7 @@ panfrost_emit_plane(const struct pan_image_view *iview,
          cfg.two_plane_yuv_chroma.secondary_pointer =
             sections[plane_index + 1].pointer;
       } else if (!panfrost_format_is_yuv(layout->format)) {
-         cfg.slice_stride = layout->nr_samples
+         cfg.slice_stride = layout->nr_samples > 1
                                ? surface_stride
                                : panfrost_get_layer_stride(layout, level);
       }