bonding: clean up style for bond_3ad.c

It's a huge mess currently, that is really hard to read. This cleanup
doesn't touch the logic at all, it only breaks easy-to-fix long lines and
updates comment styles.

CC: Jay Vosburgh <fubar@us.ibm.com>
CC: Andy Gospodarek <andy@greyhouse.net>
Signed-off-by: Veaceslav Falico <vfalico@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>