[][kernel][common][eth][Update power level parse function for the SFP]

[Description]
Refactor power level parse function for the SFP.

This patch backport from Linux-6.2.

If without this patch, some SFP module might get incorrect power level.

[Release-log]
N/A


Change-Id: If31efc9ad82ba2dcff93560a9944c49375872006
Reviewed-on: https://gerrit.mediatek.inc/c/openwrt/feeds/mtk_openwrt_feeds/+/7477455
1 file changed