hal: Remove volume boost feature for msm8960

Not supported on msm8960 platform. Fixes (removes) the non-working
in-call ui button for volume boost, and sorts the following error:

Could not find the symbol acdb_loader_reload_vocvoltable from libacdbloader.so

Change-Id: I1231c4d339bf5046058da86f7308d7b4d27f9ccd