Status update for maintainers file

[Sarah Harris]

Hi all,

I was added as a reviewer (in MAINTAINERS) for the AVR target for the duration 
of my research work using it.
The funding for my project expires in the middle of April, so I will not be 
able to provide time for reviewing patches from that point.

I'm not sure what the process is for removing my reviewer entry, but I assume 
if someone needs to be notified they'll be a member of this list.

Kind regards,
Sarah Harris