MAINTAINERS: eth: mtk: move John to CREDITS

MAINTAINERS: eth: mtk: move John to CREDITS

John is still active in other bits of the kernel but not much
on the MediaTek ethernet switch side. Our scripts report:

Subsystem MEDIATEK ETHERNET DRIVER
  Changes 81 / 384 (21%)
  Last activity: 2023-12-21
  Felix Fietkau <nbd@nbd.name>:
    Author c6d96df9fa2c 2023-05-02 00:00:00 42
    Tags c6d96df9fa2c 2023-05-02 00:00:00 48
  John Crispin <john@phrozen.org>:
  Sean Wang <sean.wang@mediatek.com>:
    Author 880c2d4b2fdf 2019-06-03 00:00:00 5
    Tags a5d75538295b 2020-04-07 00:00:00 7
  Mark Lee <Mark-MC.Lee@mediatek.com>:
    Author 8d66a8183d0c 2019-11-14 00:00:00 4
    Tags 8d66a8183d0c 2019-11-14 00:00:00 4
  Lorenzo Bianconi <lorenzo@kernel.org>:
    Author 7cb8cd4daacf 2023-12-21 00:00:00 98
    Tags 7cb8cd4daacf 2023-12-21 00:00:00 112
  Top reviewers:
    [18]: horms@kernel.org
    [15]: leonro@nvidia.com
    [8]: rmk+kernel@armlinux.org.uk
  INACTIVE MAINTAINER John Crispin <john@phrozen.org>

Reviewed-by: Simon Horman <horms@kernel.org>
Signed-off-by: John Crispin <john@phrozen.org>
Link: https://lore.kernel.org/r/20240109164517.3063131-2-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>