bonding: remove no longer needed lock for bond_xxx_info_query()

The bond_xxx_info_query() was already in RTNL, so no need to use
bond lock to protect the bond slave list, so remove it.

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