MAINTAINERS: Add entry for TQ-Systems device trees and drivers

This includes the arm & arm64 module + board DT files as well as x86
platform GPIO drivers.

Signed-off-by: Matthias Schiffer <matthias.schiffer@ew.tq-group.com>
Signed-off-by: Markus Niebel <Markus.Niebel@ew.tq-group.com>
Signed-off-by: Alexander Stein <alexander.stein@ew.tq-group.com>
Link: https://lore.kernel.org/r/20230801085158.87735-1-alexander.stein@ew.tq-group.com


Signed-off-by: Lee Jones <lee@kernel.org>