ixgbe: fix AF_XDP tx byte count

The tx bytecount is done twice.  When running
'./xdpsock -t -N -i eth3' and 'ip -s link show dev eth3'
The avg packet size is 120 instead of 60. So remove the
extra one.
Signed-off-by: William Tu <u9012063@gmail.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

drivers/net/ethernet/intel/ixgbe/ixgbe_xsk.c

@@ -654,7 +654,6 @@ bool ixgbe_clean_xdp_tx_irq(struct ixgbe_q_vector *q_vector,
 			xsk_frames++;
 
 		tx_bi->xdpf = NULL;
-		total_bytes += tx_bi->bytecount;
 
 		tx_bi++;
 		tx_desc++;