When merging NEW_TOKENSET into EC_MULTISYMBOL a bug was introduced when
 EC_MULTISYMBOL == 1 and EC_ADAPT == 0.
This patch reverts that change and replaces CONFIG_EC_MULTISYMBOL with
 the equivalent flag (CONFIG_DAALA_EC || CONFIG_ANS).

BUG=aomedia:550

Change-Id: I164df42121ca0959247af34e65287b1d230346f7