bcachefs: fix missing include

fs-common.h needs dirent.h for enum bch_rename_mode
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

fs/bcachefs/fs-common.h

@@ -2,6 +2,8 @@
 #ifndef _BCACHEFS_FS_COMMON_H
 #define _BCACHEFS_FS_COMMON_H
 
+#include "dirent.h"
+
 struct posix_acl;
 
 #define BCH_CREATE_TMPFILE		(1U << 0)