linux-phytec-ti

PCI: endpoint: Make pci_epf_driver ops optional

pci_epf_driver had two ops for bind and unbind which will be invoked
when an endpoint controller is bound to an endpoint function (using
configfs). Now that endpoint core has support to define an endpoint
function using device tree alone, the bind and unbind ops can be
optional. Make pci_epf_driver ops optional here.

Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
Signed-off-by: Sekhar Nori <nsekhar@ti.com>