Some devices lose data on TRIM whether queued or not.  This patch adds
a horkage to disable TRIM.

tj: Collapsed unnecessary if() nesting.
Signed-off-by: NArne Fitzenreiter <arne_f@ipfire.org>
Signed-off-by: NTejun Heo <tj@kernel.org>
Cc: stable@vger.kernel.org