Audio VTS was testing wrong uninitialized variable due to typo

The test was testing a uninitialized variable instead of testing
the result of the tested method.

Bug: 110963314
Test: vts-tradefed run commandAndExit vts --module VtsHalAudioV2_0Target
Change-Id: I9a212eef690ae627fd7f7dbfaf4a0b4047c491b3
Signed-off-by: Kevin Rocard <krocard@google.com>