MAINTAINERS: claim maintenance over rtl818x drivers

Michael and Andrea have moved-on, so we shouldn't be bothering them
about these drivers anymore.

Actually, Herton Ronaldo Krzesinski, Hin-Tak Leung, and Larry Finger
have been handling the rtl8187 stuff for a while.  So, I would welcome a
patch from one of them changing this to just RTL8180 and adding an
RTL8187 entry with their names...

Signed-off-by: John W. Linville <linville@tuxdriver.com>