tpm: disable the TPM if NULL name changes

Update tpm2_load_context() to return -EINVAL on integrity failures and
use this as a signal when loading the NULL context that something
might be wrong.  If the signal fails, check the name of the NULL
primary against the one stored in the chip data and if there is a
mismatch disable the TPM because it is likely to have suffered a reset
attack.

Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Tested-by: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>