Fix panic issue for mtk_pending_work. If without this patch, mtk_pending_work might cause kernel panic in the one gmac system. [Release-log] N/A Change-Id: I9d2940645d738bac8888a7410c5ad5586a08c115 Reviewed-on: https://gerrit.mediatek.inc/c/openwrt/feeds/mtk_openwrt_feeds/+/6814894