igb: move the multiple receive queue configuration into seperate function

This patch moves the multiple receive queue configuration into a seperate
function from igb_configure_rx.  We can essentially do the configuration for
the multiple receive queues just prior to enabling the RX and this will allow
us to seperate the queue enablement from the receive queue layout
configuration.

Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>