Modify firmware build to use single thread

Change build command to use a single thread for firmware compilation.

Author: reflander

.github/workflows/Build_LEDE_OP_x86_Releases.yml

@@ -85,7 +85,8 @@ jobs:
       working-directory: ./openwrt
       run: |
         echo -e "$(nproc) thread build."
-        make -j$(nproc) V=s
+        make -j1 V=s
+        # make -j$(nproc) V=s
 
             # 步骤1：生成唯一的Tag（仅用GITHUB_ENV注入，移除过时的set-output）
     - name: Generate release tag