Changes

global_platform: Add KCV computation for TLS-PSK keys

This adds support for computing the KCV (key check value) for TLS-PSK
keys such as those used in SCP81.

The spec reference is "Remote Application Management over HTTP
Card Specification v2.2 - Amendment B Version 1.1.3"

Change-Id: I8c56ba1341fd4615f8a9ed0c13f25790639f9098