Allocate eobs array per txblock and not per pixel.

Change-Id: I5368f5fc7283420c38d5bd85e3077b761d94ace6

vp9/encoder/vp9_context_tree.c

@@ -36,7 +36,7 @@ static void alloc_mode_context(VP9_COMMON *cm, int num_4x4_blk,
       CHECK_MEM_ERROR(cm, ctx->dqcoeff[i][k],
                       vpx_memalign(16, num_pix * sizeof(*ctx->dqcoeff[i][k])));
       CHECK_MEM_ERROR(cm, ctx->eobs[i][k],
-                      vpx_memalign(16, num_pix * sizeof(*ctx->eobs[i][k])));
+                      vpx_memalign(16, num_blk * sizeof(*ctx->eobs[i][k])));
       ctx->coeff_pbuf[i][k]   = ctx->coeff[i][k];
       ctx->qcoeff_pbuf[i][k]  = ctx->qcoeff[i][k];
       ctx->dqcoeff_pbuf[i][k] = ctx->dqcoeff[i][k];