i40e: remove redundant assignment

Remove a redundant assignment of the software ring pointer in the i40e
driver. The variable is assigned twice with no use in between, so just
get rid of the first occurrence.

Fixes: 3b4f0b6 ("i40e, xsk: Migrate to new MEM_TYPE_XSK_BUFF_POOL")
Signed-off-by: Marek Majtyka <marekx.majtyka@intel.com>
Acked-by: Björn Töpel <bjorn.topel@intel.com>
Tested-by: George Kuruvinakunnel <george.kuruvinakunnel@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>

drivers/net/ethernet/intel/i40e/i40e_xsk.c

@@ -311,7 +311,6 @@ int i40e_clean_rx_irq_zc(struct i40e_ring *rx_ring, int budget)
 			continue;
 		}
 
-		bi = i40e_rx_bi(rx_ring, rx_ring->next_to_clean);
 		size = (qword & I40E_RXD_QW1_LENGTH_PBUF_MASK) >>
 		       I40E_RXD_QW1_LENGTH_PBUF_SHIFT;
 		if (!size)