tpm: Rollback tpm2_load_null()

Do not continue on tpm2_create_primary() failure in tpm2_load_null().

Cc: stable@vger.kernel.org # v6.10+
Fixes: eb24c978 ("tpm: disable the TPM if NULL name changes")
Reviewed-by: Stefan Berger <stefanb@linux.ibm.com>
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>