nfs: new subdir Documentation/filesystems/nfs

We're adding enough nfs documentation that it may as well have its own
subdirectory.

Acked-by: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
diff --git a/net/ipv4/ipconfig.c b/net/ipv4/ipconfig.c
index f8d04c2..7dcbf47 100644
--- a/net/ipv4/ipconfig.c
+++ b/net/ipv4/ipconfig.c
@@ -1447,7 +1447,7 @@
 
 /*
  *  Decode any IP configuration options in the "ip=" or "nfsaddrs=" kernel
- *  command line parameter.  See Documentation/filesystems/nfsroot.txt.
+ *  command line parameter.  See Documentation/filesystems/nfs/nfsroot.txt.
  */
 static int __init ic_proto_name(char *name)
 {