MAINTAINERS: tls: move Aviad to CREDITS

Aviad wrote parts of the initial TLS implementation
but hasn't been contributing to TLS since.

Subsystem NETWORKING [TLS]
  Changes 123 / 308 (39%)
  Last activity: 2020-12-01
  Boris Pismenny <borisp@nvidia.com>:
    Tags 138559b9 2020-11-17 00:00:00 1
  Aviad Yehezkel <aviadye@nvidia.com>:
  John Fastabend <john.fastabend@gmail.com>:
    Author e91de6af 2020-06-01 00:00:00 22
    Tags e91de6af 2020-06-01 00:00:00 29
  Daniel Borkmann <daniel@iogearbox.net>:
    Author c16ee04c 2018-10-20 00:00:00 7
    Committer b8e202d1 2020-02-21 00:00:00 19
    Tags b8e202d1 2020-02-21 00:00:00 28
  Jakub Kicinski <kuba@kernel.org>:
    Author 5c39f26e 2020-11-27 00:00:00 89
    Committer d31c0800 2020-12-01 00:00:00 15
    Tags d31c0800 2020-12-01 00:00:00 117
  Top reviewers:
    [50]: dirk.vandermerwe@netronome.com
    [26]: simon.horman@netronome.com
    [14]: john.hurley@netronome.com
  INACTIVE MAINTAINER Aviad Yehezkel <aviadye@nvidia.com>

Signed-off-by: Jakub Kicinski <kuba@kernel.org>