btrfs-progs: mkfs: use correct ctree.h include

Commit 14ac1a6051 ("btrfs-progs: mkfs: add support for squota")
mistakenly added ctree.h from libbtrfs/ but this is not supposed to be
used outside of the library. Moreover the correct ctree.h was already
there.

Signed-off-by: David Sterba <dsterba@suse.com>

mkfs/main.c

@@ -65,8 +65,6 @@
 #include "mkfs/common.h"
 #include "mkfs/rootdir.h"
 
-#include "libbtrfs/ctree.h"
-
 struct mkfs_allocation {
 	u64 data;
 	u64 metadata;