Description of problem:

OCP 4.15 documentation says in multiple points that for Cloud Credentials operator configured in Mint or Passthrough mode there is no operation to do. However, for GCP there is a new role requirement for root credentials and the annotation upgradeable-to is needed for Mint and Passthrough mode too.

Steps to Reproduce:

1. Deploy a cluster 4.14 on GCP
2. Change the channel to a suitable 4.15 channel
3. OCP UI displays that upgrade to 4.15 is blocked

Actual results:

Upgrade to OCP 4.15 is blocked

Expected results:

Documentation should be consistent, the available graph should be fixed too.