Only allow audio V4 for devices targeting level 3

Device targeting the last level must use the last version of the
audio HAL.

Bug: 38184704
Test: cuttlefish has no build target, so there is no way to test,
      nevertheless the exact same trivial change was made to Pixel 2
Change-Id: If767803e08caf5b03edcea26fd8dba1cca12cc38
Signed-off-by: Kevin Rocard <krocard@google.com>