{xiaomi-once,beelink-gt1}: drop maintainership as requested (MR 5011)

exkc has stated that he cannot maintain the ports anymore,
see #postmarketos-devel discussion:

	<@f_[xmpp]> af2e02839bcfb0aae789a9ea66f63a: hiya, are you available?
	<@f_[xmpp]> It's about 2 of your Amlogic device ports. You said
	before that your beelink-gt1 and xiaomi-once were broken
	<@f_[xmpp]> are you still able to maintain these ports?
	<@f_[xmpp]> If not then they should probably be dropped.
	<af2e02839bcfb0aae789a9ea66f63a> drop them
	<@f_[xmpp]> af2e02839bcfb0aae789a9ea66f63a: sure

[ci:skip-vercheck]

Suggested-by: exkc <exxxxkc@getgoogleoff.me>
Signed-off-by: Ferass El Hafidi <funderscore@postmarketos.org>