be2net: don't create multiple RX/TX rings in multi channel mode

When the HW is in multi-channel mode based on the skew/IPL, there are
4 functions per port and so not enough resources to create multiple
RX/TX rings for each function.

Signed-off-by: Suresh Reddy <suresh.reddy@emulex.com>
Signed-off-by: Sathya Perla <sathya.perla@emulex.com>
Signed-off-by: David S. Miller <davem@davemloft.net>