MAINTAINERS: update my status

Revert to my old username on west and drop my long-inactive LED strip
involvement.

(I'm intentionally not adding myself back to the devicetree
collaborators list -- I'm not able to help out there at this time.)

Signed-off-by: Martí Bolívar <[email protected]>

Author: mbolivar

MAINTAINERS.yml

@@ -1787,7 +1787,6 @@ Release Notes:
   maintainers:
     - simonguinot
   collaborators:
-    - mbolivar-ampere
     - soburi
     - thedjnK
   files:
@@ -4519,7 +4518,7 @@ West:
   maintainers:
     - pdgendt
   collaborators:
-    - mbolivar-ampere
+    - mbolivar
     - carlescufi
     - swinslow
   files: