MAINTAINERS: remove LIBATA PATA DRIVERS entry

Even though there is not much happening for libata PATA drivers
I don't have time to look after them anymore.

Since Jens is maintaining the whole libata anyway just remove
"LIBATA PATA DRIVERS" entry.

Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>