MAINTAINERS: Add collaborator for ethernet drivers (OA TC6 and T1S)

I can help as a collaborator for the network's ethernet subsystem
(especially the OA TC6 driver).

Signed-off-by: Lukasz Majewski <lukma@denx.de>

Author: Lukasz Majewski

MAINTAINERS.yml

@@ -1233,6 +1233,7 @@ Release Notes:
   status: odd fixes
   collaborators:
     - decsny
+    - lmajewski
   files:
     - drivers/ethernet/
     - include/zephyr/dt-bindings/ethernet/