CVE-2021-46922

In the Linux kernel, the following vulnerability has been resolved:

KEYS: trusted: Fix TPM reservation for seal/unseal

The original patch 8c657a0590de (“KEYS: trusted: Reserve TPM for seal
and unseal operations”) was correct on the mailing list:

https://lore.kernel.org/linux-integrity/[email protected]/

But somehow got rebased so that the tpm_try_get_ops() in
tpm2_seal_trusted() got lost. This causes an imbalanced put of the
TPM ops and causes oopses on TIS based hardware.

This fix puts back the lost tpm_try_get_ops()