nfp: flower-ct: Fix fall-through warning for Clang

In preparation to enable -Wimplicit-fallthrough for Clang, fix the
following warning by explicitly adding a break statement:

drivers/net/ethernet/netronome/nfp/flower/conntrack.c:1175:2: warning: unannotated fall-through between switch labels [-Wimplicit-fallthrough]

Link: https://github.com/KSPP/linux/issues/115Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>

drivers/net/ethernet/netronome/nfp/flower/conntrack.c

@@ -1172,6 +1172,7 @@ int nfp_fl_ct_del_flow(struct nfp_fl_ct_map_entry *ct_map_ent)
 				       nfp_ct_map_params);
 		nfp_fl_ct_clean_flow_entry(ct_map_ent->ct_entry);
 		kfree(ct_map_ent);
+		break;
 	default:
 		break;
 	}