MAINTAINERS: removed staging/ft1000 driver

Delete the ft1000 MAINTAINERS entry, concluding the
earlier removal of the driver in commit 6512edec
("staging: ft1000: remove obsolete driver").

Reported-by: Joe Perches <joe@perches.com>
Signed-off-by: Deepa Dinamani <deepa.kernel@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>