integrity: eliminate unnecessary "Problem loading X.509 certificate" msg

Currently when the kernel fails to add a cert to the .machine keyring,
it will throw an error immediately in the function integrity_add_key.

Since the kernel will try adding to the .platform keyring next or throw
an error (in the caller of integrity_add_key i.e. add_to_machine_keyring),
so there is no need to throw an error immediately in integrity_add_key.

Reported-by: itrymybest80@protonmail.com
Closes: https://bugzilla.redhat.com/show_bug.cgi?id=2239331
Fixes: d1996776 ("integrity: Introduce a Linux keyring called machine")
Reviewed-by: Eric Snowberg <eric.snowberg@oracle.com>
Signed-off-by: Coiby Xu <coxu@redhat.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>

security/integrity/digsig.c

@@ -179,6 +179,7 @@ static int __init integrity_add_key(const unsigned int id, const void *data,
 				   KEY_ALLOC_NOT_IN_QUOTA);
 	if (IS_ERR(key)) {
 		rc = PTR_ERR(key);
+		if (id != INTEGRITY_KEYRING_MACHINE)
 			pr_err("Problem loading X.509 certificate %d\n", rc);
 	} else {
 		pr_notice("Loaded X.509 cert '%s'\n",