dwc_otg: add hacks for debugging network dropouts

- Make the HCD print out its entire internal state when smsc95xx
  detects a register read timeout
- Add a module for IRQ latency fuzz testing - irq_fuzzer.
  If inserted, this module will eat about 30% of CPU time
  randomly holding off interrupts. It will break lots of things
  in an attempt to speed up the failure of the dwc_otg HCD.

Use dwc_otg.fiq_fsm_enable=1 dwc_otg.fiq_fsm_mask=0x0
in the boot commandline.