entropy: Fix --disable-ec_multisymbol build
entropy: Fix --disable-ec_multisymbol build

Broken by I233979909118241a0c78761c1d5c2cd6857915e0

Change-Id: I3af0d3907f63b69c1301a48e7d2a276c52d3fd00

smarter/aom,luctrudeau/aom,luctrudeau/aom,smarter/aom,GrokImageCompression/aom,luctrudeau/aom,luctrudeau/aom,GrokImageCompression/aom,GrokImageCompression/aom,luctrudeau/aom,smarter/aom,luctrudeau/aom,GrokImageCompression/aom,GrokImageCompression/aom,smarter/aom,smarter/aom,smarter/aom,GrokImageCompression/aom