MAINTAINERS: hostap: Mark the Host AP driver obsolete

This is old code for old hardware and it is not really accurate to claim
this to be maintained anymore. Change the status to "Obsolete" to make
it clearer that minor cleanup and other unnecessary changes from
automated tools is not necessarily beneficial and has larger risk of
breaking something without being quickly noticed due to lack of testing.

In addition, remove the old mailing list that does not work anymore and
point the web-page to a more accurate URL.

Signed-off-by: Jouni Malinen <j@w1.fi>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>