Merge branch 'net-mediatek-Add-MT7621-TRGMII-mode-support'

René van Dorst says:

====================
net: mediatek: Add MT7621 TRGMII mode support

Like many other mediatek SOCs, the MT7621 SOC and the internal MT7530
switch both supports TRGMII mode. MT7621 TRGMII speed is fix 1200MBit.

v1->v2:
 - Fix breakage on non MT7621 SOC
 - Support 25MHz and 40MHz XTAL as MT7530 clocksource
====================

Tested-by: "Frank Wunderlich" <frank-w@public-files.de>
Acked-by: Sean Wang <sean.wang@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>