GSoC 2015 RPi USB Support

[Yurii Shevtsov]

Hello)
Now I have apps from libbsd testsuite running. But DWC OTG driver doesn't loads.
I added this lines to init01/test_main.c:

+SYSINIT_NEED_USB_CORE;
+SYSINIT_DRIVER_REFERENCE(bcm283x_dwcotg, nexus);

(I know it's bad hardcode)

If I run it. I get only this:
  nexus0: <RTEMS Nexus device>
  devctl: +nexus0 at   on root0
  devctl: !system=IFNET subsystem=lo0 type=ATTACH

Of course, I modified rtemsbsd/include/machine/rtems-bsd-sysinit.h and
rtemsbsd/include/bsp/nexus-devices.h (took vlues from working DTS) and
did other nexus-related changes to drivers. You can find changes in my
repo https://github.com/gtament/rtems-libbsd/
So I need some kind of code review, please.
P.S. All testsuites (netshell01, usb01) with shell hangs without any output.

Thanks in advance!