Allow trim on any file type

Allow trim on any file type

The mtd fio engine will support trim (interpreted as erase). There is
no particular reason to tie trims to block devices, as it is only a
particular ioengine which calls the trim ioctl, not generic code.
This patch simply removes the test which checks that trim is only
run on block devices.

Signed-off-by: Dan Ehrenberg <dehrenberg@chromium.org>
Signed-off-by: Jens Axboe <axboe@fb.com>