MFC r345438,r345842,r346259,r346261: TPM as possible entropy source
Allow using TPM as entropy source
TPM has a built-in RNG, with its own entropy source.
The driver was extended to harvest 16 random bytes from TPM every 10 seconds.
A new build option "TPM_HARVEST" was introduced - for now, however, it
is not enabled by default in the GENERIC config.
Reviewed by: markm, delphij
Approved by: secteam
Add a cv_wait to the TPM2.0 harvesting function
tpm: Prevent session hijack
Improve tpm20 style
Submitted by: Kornel Duleba <email@example.com>
Obtained from: Semihalf
Sponsored by: Stormshield