docs: update `how-to` README file for Firecracker config
Remove the `Kata Containers with Firecracker` additional configuration steps.
From kata 2.x,  the config of `firecracker` is same to `qemu` and `cloud-hypervisor`.
Fixes:
- `firecracker`
- `ACRN`
- While `qemu` and `cloud-hypervisor` work out of the box with installation of Kata,
- some additional configuration is needed in case of `firecracker` and `ACRN`.
+ While `qemu` , `cloud-hypervisor` and `firecracker` work out of the box with installation of Kata,
+ some additional configuration is needed in case of `ACRN`.
Refer to the following guides for additional configuration steps:
-- [Kata Containers with Firecracker](https://github.com/kata-containers/documentation/wiki/Initial-release-of-Kata-Containers-with-Firecracker-support)
- [Kata Containers with ACRN Hypervisor](how-to-use-kata-containers-with-acrn.md)
## Advanced Topics
