tpm: fix: allow TPM2_RC_TESTING from tpm2_start_selftest()

With the TPM2 FIFO module I have I seem to get TPM2_RC_TESTING.
This patch ignores this error code as the self-test seems to be
running without issues to the end.

Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
tpm: remove FIXME comments from platform driver deinitializations

I was able to test insmod ./tpm_tis.ko force with TPM2 FIFO
module. All the resources are cleaned up so I think it is safe
to remove FIXME comments.

Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>