ceph: mention helm upgrade path for csi driver
ceph: mention helm upgrade path for csi driver

Update documentation to mention helm chart upgrade path for csi driver.

This prevents the user from manually applying the RBAC roles when the helm chart does it for him also notifies him where to set the images for CSI in the helm chart.

Signed-off-by: Paul <7bf6d7a567a2e85bc51830421b307b9545448643@gmail.com>

rook/rook,rook/nfs,rook/rook,rook/nfs,rook/nfs,rook/rook,rook/rook,rook/rook