`-nic model=help` on qemu-system-riscv64 doesn't output supported models
Description of problem:
`-nic model=help` doesn't list out the supported NIC models and instead launches QEMU with warnings.
![image](/uploads/6b0ea448ee8757a5b14081bb19dd6060/image.png)
Steps to reproduce:
1. run `qemu-system-riscv64 -machine virt -nic model=help`