drivers/block/loop.c: fix comment typo in loop_config_discard

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>

drivers/block/loop.c

diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index 33fde3a..66e8c3b 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -799,7 +799,7 @@
 
 	/*
 	 * We use punch hole to reclaim the free space used by the
-	 * image a.k.a. discard. However we do support discard if
+	 * image a.k.a. discard. However we do not support discard if
 	 * encryption is enabled, because it may give an attacker
 	 * useful information.
 	 */