MAINTAINERS: ipvs: move Wensong Zhang to CREDITS

MAINTAINERS: ipvs: move Wensong Zhang to CREDITS

Move Wensong Zhang to credits, we haven't heard from
him in years.

Subsystem IPVS
  Changes 83 / 226 (36%)
  Last activity: 2020-11-27
  Wensong Zhang <[email protected]>:
  Simon Horman <[email protected]>:
    Committer c24b75e0f923 2019-10-24 00:00:00 33
    Tags 7980d2eabde8 2020-10-12 00:00:00 76
  Julian Anastasov <[email protected]>:
    Author 7980d2eabde8 2020-10-12 00:00:00 26
    Tags 4bc3c8dc9f5f 2020-11-27 00:00:00 78
  Top reviewers:
    [6]: [email protected]
  INACTIVE MAINTAINER Wensong Zhang <[email protected]>

Signed-off-by: Jakub Kicinski <[email protected]>