gallium/u_blitter: treat Z scaling as scaled blits

Hopefully this didn't break anything.

Acked-by: Pierre-Eric Pelloux-Prayer <pierre-eric.pelloux-prayer@amd.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/17692>

src/gallium/auxiliary/util/u_blitter.c

@@ -2041,7 +2041,8 @@ void util_blitter_blit_generic(struct blitter_context *blitter,
    }
 
    bool is_scaled = dstbox->width != abs(srcbox->width) ||
-                    dstbox->height != abs(srcbox->height);
+                    dstbox->height != abs(srcbox->height) ||
+                    dstbox->depth != abs(srcbox->depth);
 
    if (src_has_stencil || !is_scaled)
       filter = PIPE_TEX_FILTER_NEAREST;