maintainers.yml: litex: promote maass-hamburg to maintainer

promote maass-hamburg to litex maintainer.

Signed-off-by: Fin Maaß <[email protected]>

Author: maass-hamburg

MAINTAINERS.yml

@@ -3068,9 +3068,9 @@ LiteX Platforms:
     - tgorochowik
     - kgugala
     - fkokosinski
+    - maass-hamburg
   collaborators:
     - mateusz-holenko
-    - maass-hamburg
   files:
     - boards/enjoydigital/litex_vexriscv/
     - drivers/*/*litex*