bonding: Allow setting max_bonds to zero

Permit bonding to function rationally if max_bonds is set to
zero.  This will load the module, but create no master devices (which can
be created via sysfs).

	Requires some change to bond_create_sysfs; currently, the
netdev sysfs directory is determined from the first bonding device created,
but this is no longer possible.  Instead, an interface from net/core is
created to create and destroy files in net_class.

	Based on a patch submitted by Phil Oester <kernel@linuxaces.com>.
Modified by Jay Vosburgh to fix the sysfs issue mentioned above and to
update the documentation.

Signed-off-by: Phil Oester <kernel@linuxace.com>
Signed-off-by: Jay Vosburgh <fubar@us.ibm.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>

Documentation/networking/bonding.txt

@@ -376,7 +376,8 @@ max_bonds
 	Specifies the number of bonding devices to create for this
 	instance of the bonding driver.  E.g., if max_bonds is 3, and
 	the bonding driver is not already loaded, then bond0, bond1
-	and bond2 will be created.  The default value is 1.
+	and bond2 will be created.  The default value is 1.  Specifying
+	a value of 0 will load bonding, but will not create any devices.
 
 miimon