Description
In dockers/docker-orchagent/orchagent.sh
export platform=sonic-cfggen -v onie_switch_asic is not working on broadcom platform

Steps to reproduce the issue:

1. Run the command
   sonic:~$ sonic-cfggen -v onie_switch_asic

sonic:~$

Describe the results you received:
Empty

Describe the results you expected:
broadcom related key words

Additional information you deem important (e.g. issue happens only occasionally):

**Output of `show version`:**

```
(paste your output here)
```

**Attach debug file `sudo generate_dump`:**

```
(paste your output here)
```