tpm: invalid self test error message

The driver emits invalid self test error message even though the init
succeeds.

Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Fixes: cae8b441

 ("tpm: Factor out common startup code")
Reviewed-by: James Morris <james.l.morris@oracle.com>
Signed-off-by: James Morris <james.l.morris@oracle.com>