tpm: Use kfree_sensitive() to free auth session in tpm_dev_release()

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

tpm: Use kfree_sensitive() to free auth session in tpm_dev_release()

tpm_dev_release() uses plain kfree() to free chip->auth, which contains

sensitive cryptographic material including HMAC session keys, nonces,

and passphrase data (struct tpm2_auth).

Every other code path that frees this structure uses kfree_sensitive()

to zero the memory before releasing it: both tpm2_end_auth_session()

and tpm_buf_check_hmac_response() do so. The tpm_dev_release() path

is the only one that does not, leaving key material in freed slab

memory until it is eventually overwritten.

Use kfree_sensitive() for consistency with the rest of the driver and

to ensure session keys are scrubbed during device teardown.