tpm2-setup: Don't fail if we can't access the TPM due to authorization failure

tpm2-setup: Don't fail if we can't access the TPM due to authorization failure

The TPM might be password/pin protected for various reasons even if
there is no SRK yet. Let's handle those cases gracefully instead of
failing the unit as it is enabled by default.

(cherry picked from commit d6518003f8ebbfb6f85dbf227736ae05b0961199)