hal: qap-test: Fix for dolby library path in QAP

- In audio-ip-handler, fopen is used to calculate the size
  of encrypted dolby library. And fopen expects absolute
  path of the file to be opened.
- Changed to provide absolute dolby library path.

CRs-fixed: 2148462
Change-Id: I9ad2ff4fe86e584d1861e0c81775b8637c3d0732