usb: Sync receiving data from ISO OUT endpoint with SOF

This commit adds support for receiveing data from ISO OUT endpoint
for NRF devices. NRF USB IP core does not generate IRQ when
data are received on ISO OUT endpoint and it must be synchronized
with SOF event.

Enable SOF handling by default if usb audio is configured
with NRF devices.

Signed-off-by: Emil Obalski <emil.obalski@nordicsemi.no>