Add Documentation to help users use PCI endpoint to configure PCI endpoint
function and to bind the endpoint function with endpoint controller.
Signed-off-by: NKishon Vijay Abraham I <kishon@ti.com>
Acked-By: NJoao Pinto <jpinto@synopsys.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>