vc4: Fix check for tile RCL blits with mismatched y.

This was a typo in 3a508a0d94 that didn't
show up in testcases at that moment.

src/gallium/drivers/vc4/vc4_blit.c

@@ -64,7 +64,7 @@ vc4_tile_blit(struct pipe_context *pctx, const struct pipe_blit_info *info)
                 return false;
 
         if (info->dst.box.x != info->src.box.x ||
-            info->src.box.y != info->src.box.y ||
+            info->dst.box.y != info->src.box.y ||
             info->dst.box.width != info->src.box.width ||
             info->dst.box.height != info->src.box.height) {
                 return false;