MAINTAINERS: remove Sean Wang from MediaTek Ethernet and switch

MAINTAINERS: remove Sean Wang from MediaTek Ethernet and switch

We have not seen tags from Sean in over 5 years,
with only one mailing list post since 2024.
Felix and Lorenzo are active for the Ethernet driver,
and Chester, Daniel and DENG Qingfang are active for
the switch driver.

Subsystem MEDIATEK ETHERNET DRIVER
  Changes 55 / 113 (48%)
  Last activity: 2025-10-12
  Felix Fietkau <nbd@nbd.name>:
    Author d4736737110f 2025-09-02 00:00:00 3
    Tags d4736737110f 2025-09-02 00:00:00 4
  Sean Wang <sean.wang@mediatek.com>:
  Lorenzo Bianconi <lorenzo@kernel.org>:
    Author 96326447d466 2025-08-13 00:00:00 35
    Tags 3abc0e55ea1f 2025-10-12 00:00:00 40
  Top reviewers:
    [26]: horms@kernel.org
    [5]: andrew@lunn.ch
    [4]: jacob.e.keller@intel.com
    [3]: shannon.nelson@amd.com
    [3]: michal.swiatkowski@linux.intel.com
  INACTIVE MAINTAINER Sean Wang <sean.wang@mediatek.com>

Subsystem MEDIATEK SWITCH DRIVER
  Changes 26 / 70 (37%)
  Last activity: 2025-12-01
  Chester A. Unal <chester.a.unal@arinc9.com>:
    Tags 585943b7ad30 2025-12-01 00:00:00 7
  Daniel Golle <daniel@makrotopia.org>:
    Author 497041d76301 2025-04-23 00:00:00 2
    Tags 3b87e60d2131 2025-12-01 00:00:00 14
  DENG Qingfang <dqfext@gmail.com>:
  Sean Wang <sean.wang@mediatek.com>:
  Top reviewers:
    [4]: andrew@lunn.ch
    [4]: florian.fainelli@broadcom.com
    [4]: arinc.unal@arinc9.com
    [2]: olteanv@gmail.com
  INACTIVE MAINTAINER Sean Wang <sean.wang@mediatek.com>

Acked-by: Chester A. Unal <chester.a.unal@arinc9.com>
Link: https://patch.msgid.link/20260303215339.2333548-6-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>