ixgbe, xsk: Get rid of redundant 'fallthrough'

Intel drivers translate actions returned from XDP programs to their own
return codes that have the following mapping:

XDP_REDIRECT -> IXGBE_XDP_{REDIR,CONSUMED}
XDP_TX -> IXGBE_XDP_{TX,CONSUMED}
XDP_DROP -> IXGBE_XDP_CONSUMED
XDP_ABORTED -> IXGBE_XDP_CONSUMED
XDP_PASS -> IXGBE_XDP_PASS

Commit c7dd09fd ("ixgbe, xsk: Terminate Rx side of NAPI when XSK Rx
queue gets full") introduced new translation

XDP_REDIRECT -> IXGBE_XDP_EXIT

which is set when XSK RQ gets full and to indicate that driver should
stop further Rx processing. This happens for unsuccessful
xdp_do_redirect() so it is valuable to call trace_xdp_exception() for
this case. In order to avoid IXGBE_XDP_EXIT -> IXGBE_XDP_CONSUMED
overwrite, XDP_DROP case was moved above which in turn made the
'fallthrough' that is in XDP_ABORTED useless as it became the last label
in the switch statement.

Simply drop this leftover.

Fixes: c7dd09fd ("ixgbe, xsk: Terminate Rx side of NAPI when XSK Rx queue gets full")
Signed-off-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20220421132126.471515-2-maciej.fijalkowski@intel.com

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

@@ -144,7 +144,6 @@ static int ixgbe_run_xdp_zc(struct ixgbe_adapter *adapter,
 		result = IXGBE_XDP_CONSUMED;
 out_failure:
 		trace_xdp_exception(rx_ring->netdev, xdp_prog, act);
-		fallthrough; /* handle aborts by dropping packet */
 	}
 	return result;
 }