bhyve: fix hostbridge device command generation

Addition of the hostbridge device was mistakenly placed to
bhyveBuildNetArgStr(). This could result in hostbridge device not being
added to the commandline if there are no network devices specified, but
hostbridge device should be added unconditionally.

Fix by placing it to virBhyveProcessBuildBhyveCmd().

src/bhyve/bhyve_command.c

@@ -173,7 +173,6 @@ bhyveBuildNetArgStr(const virDomainDef *def, virCommandPtr cmd)
         return -1;
     }
 
-    virCommandAddArgList(cmd, "-s", "0:0,hostbridge", NULL);
     virCommandAddArg(cmd, "-s");
     virCommandAddArgFormat(cmd, "1:0,virtio-net,%s", realifname);
 
@@ -268,6 +267,7 @@ virBhyveProcessBuildBhyveCmd(bhyveConnPtr driver ATTRIBUTE_UNUSED,
     virCommandAddArg(cmd, "-H"); /* vmexit from guest on hlt */
     virCommandAddArg(cmd, "-P"); /* vmexit from guest on pause */
 
+    virCommandAddArgList(cmd, "-s", "0:0,hostbridge", NULL);
     /* Devices */
     if (bhyveBuildNetArgStr(vm->def, cmd) < 0)
         goto error;