btrfs: move fs_info::fs_frozen to the flags

We can keep the state among the other fs_info flags, there's no reason
why fs_frozen would need to be separate.

Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index f0f5f28..6375e57 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -716,6 +716,8 @@
 #define BTRFS_FS_LOG1_ERR			12
 #define BTRFS_FS_LOG2_ERR			13
 #define BTRFS_FS_QUOTA_OVERRIDE			14
+/* Used to record internally whether fs has been frozen */
+#define BTRFS_FS_FROZEN				15
 
 /*
  * Indicate that a whole-filesystem exclusive operation is running
@@ -1107,9 +1109,6 @@
 	 */
 	struct list_head pinned_chunks;
 
-	/* Used to record internally whether fs has been frozen */
-	int fs_frozen;
-
 	/* Cached block sizes */
 	u32 nodesize;
 	u32 sectorsize;