dm crypt: update URLs to new cryptsetup project page

Cryptsetup home page moved to GitLab.
Also remove link to abandonded Truecrypt page.

Signed-off-by: Milan Broz <gmazyland@gmail.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
diff --git a/drivers/md/dm-crypt.c b/drivers/md/dm-crypt.c
index 713a962..ea09d54 100644
--- a/drivers/md/dm-crypt.c
+++ b/drivers/md/dm-crypt.c
@@ -228,7 +228,7 @@
  *
  * tcw:  Compatible implementation of the block chaining mode used
  *       by the TrueCrypt device encryption system (prior to version 4.1).
- *       For more info see: http://www.truecrypt.org
+ *       For more info see: https://gitlab.com/cryptsetup/cryptsetup/wikis/TrueCryptOnDiskFormat
  *       It operates on full 512 byte sectors and uses CBC
  *       with an IV derived from initial key and the sector number.
  *       In addition, whitening value is applied on every sector, whitening