[][kernel][common][eth][Fix Coverity scan warning]

[Description]
Fix Coverity scan warning.

[Release-log]
N/A


Change-Id: I7867c00156d1e439071cd8e606212d4ae011a52a
Reviewed-on: https://gerrit.mediatek.inc/c/openwrt/feeds/mtk_openwrt_feeds/+/6840068
5 files changed