MAINTAINERS: uDPU: add remaining Methode boards

Methode also has eDPU which is based on uDPU, so add eDPU as well
as the common uDPU DTSI.

Signed-off-by: Robert Marko <robert.marko@sartura.hr>
Signed-off-by: Gregory CLEMENT <gregory.clement@bootlin.com>