trusty: keymaster: Remove legacy support

Library based HALs have been deprecated for several years now, and
Keymaster 2 based testing is woefully out of date compared to running
VTS against the modern 3.0 and 4.0 implementations.

Purging these modules and their resulting dependencies will make it
easier for the central system/keymaster repository to move forwards.

Test: mm
Bug: 150239636
Change-Id: Ic2ddbe685a50e65f9db25f682ad33105195efa8a