Correct the list of supported drivers.

- bnxt(4) is supported via iflib.
- mlx4en(4) support has not yet been committed.

share/man/man4/netdump.4

@@ -24,7 +24,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd May 17, 2018
+.Dd June 8, 2018
 .Dt NETDUMP 4
 .Os
 .Sh NAME
@@ -99,12 +99,12 @@ message to the server.
 The following network drivers support netdump:
 .Xr alc 4 ,
 .Xr bge 4 ,
+.Xr bnxt 4 ,
 .Xr bxe 4 ,
 .Xr cxgb 4 ,
 .Xr em 4 ,
 .Xr igb 4 ,
 .Xr ix 4 ,
-.Xr mlx4en 4 ,
 .Xr re 4 ,
 .Xr vtnet 4 .
 .Sh SYSCTL VARIABLES