md/r5cache: r5cache recovery: part 2

1. In previous patch, we:
      - add new data to r5l_recovery_ctx
      - add new functions to recovery write-back cache
   The new functions are not used in this patch, so this patch does not
   change the behavior of recovery.

2. In this patchpatch, we:
      - modify main recovery procedure r5l_recovery_log() to call new
        functions
      - remove old functions

Signed-off-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Shaohua Li <shli@fb.com>
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index 17cf98e..aa4968c 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -7100,7 +7100,8 @@
 
 		pr_debug("md/raid:%s: using device %s as journal\n",
 			 mdname(mddev), bdevname(journal_dev->bdev, b));
-		r5l_init_log(conf, journal_dev);
+		if (r5l_init_log(conf, journal_dev))
+			goto abort;
 	}
 
 	return 0;