integrity: Replace integrity_audit_message() with integrity_audit_msg()

Now that integrity_audit_msg() accepts an errno parameter, it is
equivalent to integrity_audit_message(). Replace the remaining
integrity_audit_message() call sites with integrity_audit_msg() and remove
integrity_audit_message().

Signed-off-by: Frederick Lawler <fred@cloudflare.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>