apparmor: fix typo in kernel doc

Fix the typo in the function documentation to please kernel doc
warnings.

Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: John Johansen <john.johansen@canonical.com>

security/apparmor/lsm.c

@@ -1124,7 +1124,7 @@ static int apparmor_socket_create(int family, int type, int protocol, int kern)
  * @sock: socket that is being setup
  * @family: family of socket being created
  * @type: type of the socket
- * @ptotocol: protocol of the socket
+ * @protocol: protocol of the socket
  * @kern: socket is a special kernel socket
  *
  * Note: