remove duplicate judgment (#1432)

Co-authored-by: zhangchao3 <zhangchao3@corp.netease.com>

src/directives/loading.ts

@@ -24,9 +24,7 @@ const loadingDirective: Directive = {
     if (!instance) return;
     instance.setTip(el.getAttribute('loading-tip'));
     if (binding.oldValue !== binding.value) {
-      if (binding.oldValue !== binding.value) {
-        instance.setLoading?.(binding.value && !instance.loading);
-      }
+      instance.setLoading?.(binding.value && !instance.loading);
     }
   },
   unmounted(el) {