Fix memory overflow in av1_cdef_search()
Fix memory overflow in av1_cdef_search()

The logic to check for frame boundary needs to take 128 superblock size
into account when ext-partition is on.

BUG=aomedia:1268

Change-Id: I40d2128d5ab46d57ecab9c9ecbef122005fe4b11

GrokImageCompression/aom,GrokImageCompression/aom,GrokImageCompression/aom,GrokImageCompression/aom,GrokImageCompression/aom,GrokImageCompression/aom