MAINTAINERS: 8250: remove website reference

This website is obsolete, as it has not been updated in more than a decade.

Cc: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Baruch Siach <baruch@tkos.co.il>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>