btrfs: send: simplify includes

We don't need the whole ctree.h in send.h, none of the data types
defined there are used.
Signed-off-by: David Sterba <dsterba@suse.com>

fs/btrfs/send.c

@@ -17,6 +17,7 @@
 #include <linux/crc32c.h>
 
 #include "send.h"
+#include "ctree.h"
 #include "backref.h"
 #include "locking.h"
 #include "disk-io.h"

fs/btrfs/send.h

@@ -7,7 +7,7 @@
 #ifndef BTRFS_SEND_H
 #define BTRFS_SEND_H
 
-#include "ctree.h"
+#include <linux/types.h>
 
 #define BTRFS_SEND_STREAM_MAGIC "btrfs-stream"
 #define BTRFS_SEND_STREAM_VERSION 2
@@ -18,6 +18,9 @@
  */
 #define BTRFS_SEND_BUF_SIZE_V1				SZ_64K
 
+struct inode;
+struct btrfs_ioctl_send_args;
+
 enum btrfs_tlv_type {
 	BTRFS_TLV_U8,
 	BTRFS_TLV_U16,