In order to be able to communicate with the 88e6341 switch some pins
have to be repurposed as RGMII and SMI pins.

This fixes ethernet support on system booted via a bootloader that
has not already configured those pins (e.g. mainline u-boot, or vendor
u-boot compiled without ethernet support).
Signed-off-by: Remi Pommarel <repk@triplefau.lt>
Signed-off-by: Gregory CLEMENT <gregory.clement@bootlin.com>