econet: en7528: add PCIe and WiFi support

econet: en7528: add PCIe and WiFi support

Add PCIe controller and PHY support for EN7528 SoC. This includes
a new PCIe PHY driver, EN7528-specific startup in the MediaTek PCIe
controller, and a fix for bogus prefetch window reads on bridges
that do not implement the registers.

Enable WiFi for the DASAN H660GM-A board with MT7603 (2.4 GHz) and
MT7615/MT7663 (5 GHz).

Signed-off-by: Ahmed Naseef <naseefkm@gmail.com>
Link: https://github.com/openwrt/openwrt/pull/21326
Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>