Fix decoding failure in cb4x4 and var-tx mode
Fix decoding failure in cb4x4 and var-tx mode

Fix the bit-stream decoding failure introduced lately in cb4x4
and var-tx mode.

Change-Id: Id671b5ec98b32d65e4fb45812ee8d1b7037fd6ec

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