ice: Remove two impossible branches on XDP Tx cleaning

The tagged commit started sending %XDP_TX frames from XSk Rx ring
directly without converting it to an &xdp_frame. However, when XSk is
enabled on a queue pair, it has its separate Tx cleaning functions, so
neither ice_clean_xdp_irq() nor ice_unmap_and_free_tx_buf() ever happens
there.
Remove impossible branches in order to reduce the diffstat of the
upcoming change.

Fixes: a24b4c6e ("ice: xsk: Do not convert to buff to frame for XDP_TX")
Suggested-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
Signed-off-by: Alexander Lobakin <alexandr.lobakin@intel.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
Link: https://lore.kernel.org/bpf/20230210170618.1973430-4-alexandr.lobakin@intel.com

drivers/net/ethernet/intel/ice/ice_txrx.c

@@ -116,10 +116,7 @@ ice_unmap_and_free_tx_buf(struct ice_tx_ring *ring, struct ice_tx_buf *tx_buf)
 		if (tx_buf->tx_flags & ICE_TX_FLAGS_DUMMY_PKT) {
 			devm_kfree(ring->dev, tx_buf->raw_buf);
 		} else if (ice_ring_is_xdp(ring)) {
-			if (ring->xsk_pool)
-				xsk_buff_free(tx_buf->xdp);
-			else
-				page_frag_free(tx_buf->raw_buf);
+			page_frag_free(tx_buf->raw_buf);
 		} else {
 			dev_kfree_skb_any(tx_buf->skb);
 		}

drivers/net/ethernet/intel/ice/ice_txrx_lib.c

@@ -275,10 +275,7 @@ static u32 ice_clean_xdp_irq(struct ice_tx_ring *xdp_ring)
 		ready_frames -= frags + 1;
 		xdp_tx++;
 
-		if (xdp_ring->xsk_pool)
-			xsk_buff_free(tx_buf->xdp);
-		else
-			ice_clean_xdp_tx_buf(xdp_ring, tx_buf);
+		ice_clean_xdp_tx_buf(xdp_ring, tx_buf);
 		ntc++;
 		if (ntc == cnt)
 			ntc = 0;