ext4: correct some stale comment of criteria

We named criteria with CR_XXX, correct stale comment to criteria with
raw number.
Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
Reviewed-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com>
Link: https://lore.kernel.org/r/20230801143204.2284343-11-shikemeng@huaweicloud.comSigned-off-by: Theodore Ts'o <tytso@mit.edu>

fs/ext4/mballoc.c

@@ -2782,8 +2782,8 @@ ext4_mb_regular_allocator(struct ext4_allocation_context *ac)
 
 	/*
 	 * ac->ac_2order is set only if the fe_len is a power of 2
-	 * if ac->ac_2order is set we also set criteria to 0 so that we
-	 * try exact allocation using buddy.
+	 * if ac->ac_2order is set we also set criteria to CR_POWER2_ALIGNED
+	 * so that we try exact allocation using buddy.
 	 */
 	i = fls(ac->ac_g_ex.fe_len);
 	ac->ac_2order = 0;
@@ -2840,8 +2840,8 @@ ext4_mb_regular_allocator(struct ext4_allocation_context *ac)
 			/*
 			 * Batch reads of the block allocation bitmaps
 			 * to get multiple READs in flight; limit
-			 * prefetching at cr=0/1, otherwise mballoc can
-			 * spend a lot of time loading imperfect groups
+			 * prefetching at inexpensive CR, otherwise mballoc
+			 * can spend a lot of time loading imperfect groups
 			 */
 			if ((prefetch_grp == group) &&
 			    (ext4_mb_cr_expensive(cr) ||