Discard requests are ignored if the encryption is enabled for the given
loop device. Update comment to match the code, and similar comments
elsewhere in the file.
Signed-off-by: Olaf Hering <olaf@aepfle.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>