fs: update location of filesystems documentation

The filesystem documentation was moved from DocBook to
Documentation/filesystems/. Update it at the sources.

Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
diff --git a/fs/debugfs/file.c b/fs/debugfs/file.c
index 354e2ab..6dabc4a 100644
--- a/fs/debugfs/file.c
+++ b/fs/debugfs/file.c
@@ -9,7 +9,7 @@
  *	2 as published by the Free Software Foundation.
  *
  *  debugfs is for people to use instead of /proc or /sys.
- *  See Documentation/DocBook/filesystems for more details.
+ *  See Documentation/filesystems/ for more details.
  *
  */
 
diff --git a/include/linux/debugfs.h b/include/linux/debugfs.h
index 9174b0d..aa86e6d 100644
--- a/include/linux/debugfs.h
+++ b/include/linux/debugfs.h
@@ -9,7 +9,7 @@
  *	2 as published by the Free Software Foundation.
  *
  *  debugfs is for people to use instead of /proc or /sys.
- *  See Documentation/DocBook/filesystems for more details.
+ *  See Documentation/filesystems/ for more details.
  */
 
 #ifndef _DEBUGFS_H_
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index e4587eb..b7882d4 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -286,7 +286,7 @@
 	  write to these files.
 
 	  For detailed documentation on the debugfs API, see
-	  Documentation/DocBook/filesystems.
+	  Documentation/filesystems/.
 
 	  If unsure, say N.