[][Kernel][common][eth][Add Maxlinear GPY PHY driver]

[Description]
Add Maxlinear GPY PHY driver.

When GPY211 link up 2500BASE-T, MAC driver will config SGMII 2.5G FORCE mode by mtk_sgmii_setup_mode_force().
When GPY211 link up 1000BASE-T/100BASE-T/10BASE-T, MAC driver will config SGMII 1G AN mode by mtk_sgmii_setup_mode_an().

[Release-log]
N/A

Change-Id: Iea7481383f00010b9402a9709c6ae3002a048e81
Reviewed-on: https://gerrit.mediatek.inc/c/openwrt/feeds/mtk_openwrt_feeds/+/6328544
1 file changed