bonding: move active_slave setting into separate function

Do a bit of refactoring on the way.

Signed-off-by: Jiri Pirko <jiri@resnulli.us>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --cc drivers/net/bonding/bond_options.c
Simple merge

diff --cc drivers/net/bonding/bond_sysfs.c
Simple merge

diff --cc drivers/net/bonding/bonding.h
Simple merge