[IPV4]: Fix ip command line processing.

Recently the documentation in Documentation/nfsroot.txt was
update to note that in fact ip=off and ip=::::::off as the
latter is ignored and the default (on) is used.

This was certainly a step in the direction of reducing confusion.
But it seems to me that the code ought to be fixed up so that
ip=::::::off actually turns off ip autoconfiguration.

This patch also notes more specifically that ip=on (aka ip=::::::on)
is the default.

Signed-off-by: Simon Horman <horms@verge.net.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/Documentation/nfsroot.txt b/Documentation/nfsroot.txt
index 9b956a9..c86dd38 100644
--- a/Documentation/nfsroot.txt
+++ b/Documentation/nfsroot.txt
@@ -97,10 +97,6 @@
   autoconfiguration will take place.  The most common way to use this
   is "ip=dhcp".
 
-  Note that "ip=off" is not the same thing as "ip=::::::off", because in
-  the latter autoconfiguration will take place if any of DHCP, BOOTP or RARP
-  are compiled in the kernel.
-
   <client-ip>	IP address of the client.
 
   		Default:  Determined using autoconfiguration.
@@ -150,6 +146,7 @@
 
                   off or none: don't use autoconfiguration
 		  on or any:   use any protocol available in the kernel
+			       (default)
 		  dhcp:        use DHCP
 		  bootp:       use BOOTP
 		  rarp:        use RARP