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 d473673 2025-09-02 00:00:00 3
    Tags d473673 2025-09-02 00:00:00 4
  Sean Wang <sean.wang@mediatek.com>:
  Lorenzo Bianconi <lorenzo@kernel.org>:
    Author 9632644 2025-08-13 00:00:00 35
    Tags 3abc0e5 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 585943b 2025-12-01 00:00:00 7
  Daniel Golle <daniel@makrotopia.org>:
    Author 497041d 2025-04-23 00:00:00 2
    Tags 3b87e60 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>

Author: kuba-moo

MAINTAINERS

@@ -16157,7 +16157,6 @@ F:	drivers/dma/mediatek/
 
 MEDIATEK ETHERNET DRIVER
 M:	Felix Fietkau <nbd@nbd.name>
-M:	Sean Wang <sean.wang@mediatek.com>
 M:	Lorenzo Bianconi <lorenzo@kernel.org>
 L:	netdev@vger.kernel.org
 S:	Maintained
@@ -16351,7 +16350,6 @@ MEDIATEK SWITCH DRIVER
 M:	Chester A. Unal <chester.a.unal@arinc9.com>
 M:	Daniel Golle <daniel@makrotopia.org>
 M:	DENG Qingfang <dqfext@gmail.com>
-M:	Sean Wang <sean.wang@mediatek.com>
 L:	netdev@vger.kernel.org
 S:	Maintained
 F:	drivers/net/dsa/mt7530-mdio.c