tpm2: change tpm2_parse_pcr_argument() parameters to parse to Tpm2PCRValue array

tpm2: change tpm2_parse_pcr_argument() parameters to parse to Tpm2PCRValue array

In order to allow users to specify expected PCR values, change the
tpm2_parse_pcr_argument() to parse the text argument into an array of
Tpm2PCRValue objects, which provide not only the selected PCR indexes, but also
(optionally) the hash algorithm and hash value for each PCR index.