btrfs: move struct reserve_ticket definition to space-info.c

It's not used anywhere outside space-info.c so move it from space-info.h
into space-info.c.

Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

Author: fdmanana

fs/btrfs/space-info.c

@@ -173,6 +173,15 @@
  *   thing with or without extra unallocated space.
  */
 
+struct reserve_ticket {
+	u64 bytes;
+	int error;
+	bool steal;
+	struct list_head list;
+	wait_queue_head_t wait;
+	spinlock_t lock;
+};
+
 /*
  * after adding space to the filesystem, we need to clear the full flags
  * on all the space infos.

fs/btrfs/space-info.h

@@ -224,15 +224,6 @@ struct btrfs_space_info {
 	s64 reclaimable_bytes;
 };
 
-struct reserve_ticket {
-	u64 bytes;
-	int error;
-	bool steal;
-	struct list_head list;
-	wait_queue_head_t wait;
-	spinlock_t lock;
-};
-
 static inline bool btrfs_mixed_space_info(const struct btrfs_space_info *space_info)
 {
 	return ((space_info->flags & BTRFS_BLOCK_GROUP_METADATA) &&