statmount: fix security option retrieval

Fix the inverted check for security_sb_show_options().

Link: https://lore.kernel.org/r/c8eaa647-5d67-49b6-9401-705afcb7e4d7@stanley.mountain
Link: https://lore.kernel.org/r/20241120-verehren-rhabarber-83a11b297bcc@brauner


Fixes: aefff51e ("statmount: retrieve security mount options")
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
Cc: stable@vger.kernel.org # mainline only
Signed-off-by: Christian Brauner <brauner@kernel.org>