LinuxKPI: usb: factor out struct device initialization

[bz]

Summary

We never go through the device_create*() path in LinuxKPI which would
initialize some of the struct device information.

Similar to the lkpifill_pci_dev() function (which also does a lot of
pdev initialization) start a lkpi_usb_fill_dev() version which sets
the appropriate fields. Once SDIO is done I should revisit this and
see if it can be a common function between all bus attachments.

The main reason for this is to initialize der devres list and lock.

Sponsored by: The FreeBSD Foundation
MFC after: 3 days