Making deringing buffer only one row of superblocks at a time
Making deringing buffer only one row of superblocks at a time

This introduces a line buffer that hold the last three lines of each original
row so that the next row can be deringed with the original input of the upper
row.

No change in output

Change-Id: I8fad3bc48745e9ce3e440289f453477a0c5442c0

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