Since we support multiple dwc3 controllers to be existent at the same
time, in order to handle the interrupts of a particular dwc3 controller
usb_gadget_handle_interrutps should take controller index as an
argument.

Hence the API of usb_gadget_handle_interrupts is modified to take
controller index as an argument and made the corresponding changes to all
the usb_gadget_handle_interrupts calls.

Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
Reviewed-by: Lukasz Majewski <l.majewski@samsung.com>