It was a mess, a mix of crypto_* and cbc_mac calls. I made everything call crypto
functions, and also separate key setup from cryptographic operations, this will
be useful to speed up the code in the upcoming commits. Drop support for "usbotp"
key, since the crypto code for that was never mainlined and we can always get the
keys from a device as long as we have code execution (using the DCP debug registers).
Change-Id: I7aa24d12207ffb744225d1b9cc7cb1dc7281dd22
