MAINTAINERS: Add me to Android drivers

I am one of the main engineers working on ashmem. I have been fixing
bugs in the driver and have been involved in the memfd conversion
discussions and sending patches about that. I also have an understanding
of the binder driver and was involved with some of the development on
finer grained locking. So I would like to be added to the MAINTAINERS
file for android drivers for review and maintenance of ashmem and other
Android drivers.

Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Acked-by: Todd Kjos <tkjos@android.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>