update-docs-for-calico-in-centos (#10417)

docs/centos.md

@@ -7,10 +7,6 @@ Kubespray supports multiple ansible versions but only the default (5.x) gets wid
 
 ## CentOS 8
 
-CentOS 8 / Oracle Linux 8,9 / AlmaLinux 8,9 / Rocky Linux 8,9 ship only with iptables-nft (ie without iptables-legacy similar to RHEL8)
-The only tested configuration for now is using Calico CNI
-You need to add `calico_iptables_backend: "NFT"` to your configuration.
-
 If you have containers that are using iptables in the host network namespace (`hostNetwork=true`),
 you need to ensure they are using iptables-nft.
 An example how k8s do the autodetection can be found [in this PR](https://github.com/kubernetes/kubernetes/pull/82966)

docs/rhel.md

@@ -29,10 +29,6 @@ If the RHEL 7/8 hosts are already registered to a valid Red Hat support subscrip
 
 ## RHEL 8
 
-RHEL 8 ships only with iptables-nft (ie without iptables-legacy)
-The only tested configuration for now is using Calico CNI
-You need to use K8S 1.17+ and to add `calico_iptables_backend: "NFT"` to your configuration
-
 If you have containers that are using iptables in the host network namespace (`hostNetwork=true`),
 you need to ensure they are using iptables-nft.
 An example how k8s do the autodetection can be found [in this PR](https://github.com/kubernetes/kubernetes/pull/82966)