bcache-tools: display obsoleted bucket size configuration

Although BCH_FEATURE_INCOMPAT_LARGE_BUCKET is obsoleted and we don't
support it anymore,  we still need to display the obsoleted bucket
size combines by,
	bucket_size + (obso_bucket_size_hi << 16)
for the legancy consistency purpose.

This patch checks bch_has_feature_obso_large_bucket() in to_cache_sb(),
if it is true, still try to combine and display the bucket size from
obso_bucket_size_hi.

Signed-off-by: Coly Li <colyli@suse.de>
diff --git a/lib.c b/lib.c
index 8e7da8b..b005eb5 100644
--- a/lib.c
+++ b/lib.c
@@ -783,9 +783,13 @@
 		sb->feature_ro_compat = le64_to_cpu(sb_disk->feature_ro_compat);
 	}
 
-	if (sb->version >= BCACHE_SB_VERSION_CDEV_WITH_FEATURES &&
-	    bch_has_feature_large_bucket(sb))
-		sb->bucket_size = 1 << le16_to_cpu(sb_disk->bucket_size);
+	if (sb->version >= BCACHE_SB_VERSION_CDEV_WITH_FEATURES) {
+		if (bch_has_feature_large_bucket(sb))
+			sb->bucket_size = 1 << le16_to_cpu(sb_disk->bucket_size);
+		else if (bch_has_feature_obso_large_bucket(sb))
+			sb->bucket_size +=
+				le16_to_cpu(sb_disk->obso_bucket_size_hi) << 16;
+	}
 
 	return sb;
 }