Increase min size of compressed data

This commit increases the minimum size for allocated buffer for
compressed data. The old size underestimated the size needed for
small images with width or height less than 64 pixels.

BUG=https://bugs.chromium.org/p/aomedia/issues/detail?id=31

Change-Id: Ia12507edc2be1e737ec49c32f64fd2ebf1eab41f
1 file changed