MAINTAINERS: Remove Dave Goodell from the usnic RDMA driver maintainer list

The e-mail address dgoodell@exch.cisco.com no longer exists. Additionally,
according to https://www.linkedin.com/in/goodell/

 Dave is an Amazon
employee since December 2017. Hence remove his Cisco e-mail address from
the usnic maintainer list.

Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com>
Acked-by: Christian Benvenuti <benve@cisco.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>