selftests: bonding: do not set port down when adding to bond

Similar to commit be809424 ("selftests: bonding: do not set port down
before adding to bond"). The bond-arp-interval-causes-panic test failed
after commit a4abfa62 ("net: rtnetlink: Enslave device before bringing
it up") as the kernel will set the port down _after_ adding to bond if setting
port down specifically.

Fix it by removing the link down operation when adding to bond.

Fixes: 2ffd5732 ("selftests: bonding: cause oops in bond_rr_gen_slave_id")
Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>
Tested-by: Benjamin Poirier <benjamin.poirier@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

tools/testing/selftests/drivers/net/bonding/bond-arp-interval-causes-panic.sh

@@ -30,16 +30,16 @@ ip netns exec server ip addr add ${server_ip4}/24 dev eth0
 
 ip netns exec client ip link add dev bond0 down type bond mode 1 \
 	miimon 100 all_slaves_active 1
-ip netns exec client ip link set dev eth0 down master bond0
+ip netns exec client ip link set dev eth0 master bond0
 ip netns exec client ip link set dev bond0 up
 ip netns exec client ip addr add ${client_ip4}/24 dev bond0
 ip netns exec client ping -c 5 $server_ip4 >/dev/null
 
-ip netns exec client ip link set dev eth0 down nomaster
+ip netns exec client ip link set dev eth0 nomaster
 ip netns exec client ip link set dev bond0 down
 ip netns exec client ip link set dev bond0 type bond mode 0 \
 	arp_interval 1000 arp_ip_target "+${server_ip4}"
-ip netns exec client ip link set dev eth0 down master bond0
+ip netns exec client ip link set dev eth0 master bond0
 ip netns exec client ip link set dev bond0 up
 ip netns exec client ping -c 5 $server_ip4 >/dev/null