[][kernel][mt7988][i2.5gphy][net: phy: Fix AN flow for ethtool manipulation]

[Description]
Fix AN flow for ethtool manipulation. C45 config_aneg API won't manipulate
adv_1G bit correctly. So customize one. Now, we can use ethtool to switch
i2.5Gphy's speed correctly.

[Release-log]
N/A

Change-Id: Icd7ed5dec7eb54a7e6364150a450d82eedcb1779
Reviewed-on: https://gerrit.mediatek.inc/c/openwrt/feeds/mtk_openwrt_feeds/+/6993205
1 file changed