MAINTAINERS: Update mwifiex maintainer list

We haven't heard anything from these folks in years. I've been reviewing
many submissions and plan to keep doing so.

Cc: Amitkumar Karwar <amitkarwar@gmail.com>
Cc: Ganapathi Bhat <ganapathi017@gmail.com>
Cc: Sharvari Harisangam <sharvari.harisangam@nxp.com>
Cc: Xinming Hu <huxinming820@gmail.com>
Signed-off-by: Brian Norris <briannorris@chromium.org>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/20230721160603.1.Idf0e8025f59c62d73c08960638249b58cf215acc@changeid