COSE unprotected parameters are a map not a bstr

As per RFC 8152 section 3, the unprotected parameters in the headers
of COSE objects are just encoded as a map, not as a bstr that contains
the CBOR-encoding of a map.

Test: TreeHugger presubmit
Change-Id: Id4eeb023d3a81ad1398d78d410c8224bf941f9b1
7 files changed