[][kernel][mt7988][eth][Update register of mdio-bus for gphycalibration in DSA]

[Description]
Change register of mdio-bus from gbus to slave_mii_bus.

[Release-log]
N/A


Change-Id: Icadaeed161fedbd336dee9940b61bdca800a68d5
Reviewed-on: https://gerrit.mediatek.inc/c/openwrt/feeds/mtk_openwrt_feeds/+/6623821
Build: srv_hbgsm110
2 files changed