[][kernel][mt7988][eth][Add SFP support based on the DSA-10G DTS]

[Description]
Add SFP support based on the DSA-10G DTS.

Without this patch, our SDK is not capable of running both the SFP and
the switch DSA framework at the same time.

[Release-log]
N/A


Change-Id: I49880f73302601686722fb3dc2dc28dd27439559
Reviewed-on: https://gerrit.mediatek.inc/c/openwrt/feeds/mtk_openwrt_feeds/+/7989435
3 files changed