cryptsetup-generator: do not bind to the decrypted device unit (#6538)

This breaks things when the decrypted device is not immediately
`SYSTEMD_READY=1` (e. g. when a multi-device btrfs system is placed on
multiple cryptsetup devices).

Fixes #6537.

src/cryptsetup/cryptsetup-generator.c

@@ -109,7 +109,6 @@ static int create_disk(
                        "SourcePath=/etc/crypttab\n"
                        "DefaultDependencies=no\n"
                        "Conflicts=umount.target\n"
-                       "BindsTo=dev-mapper-%i.device\n"
                        "IgnoreOnIsolate=true\n"
                        "After=cryptsetup-pre.target\n",
                        f);