bonding: remove pr_fmt from bond_3ad.c

To maintain the same message structure as netdev_* functions print.

CC: Jay Vosburgh <j.vosburgh@gmail.com>
CC: Andy Gospodarek <andy@greyhouse.net>
Signed-off-by: NVeaceslav Falico <vfalico@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/bonding/bond_3ad.c

@@ -20,8 +20,6 @@
  *
  */
 
-#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
-
 #include <linux/skbuff.h>
 #include <linux/if_ether.h>
 #include <linux/netdevice.h>