efi_driver: provide driver binding protocol to bind function

efi_driver: provide driver binding protocol to bind function

DisconnectController() is based on the open protocol information created
when the driver opens a protocol with BY_CHILD_CONTROLLER or BY_DRIVER.

To create an open protocol information it is required to supply the handle
of the driver as agent handle. This information is available as field
DriverBindingHandle in the driver binding protocol.

Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>