New revision of the Sigmatel irda driver.  This version has much
better performance and doesn't drop frames in FIR mode.
Tested with both UHCI and EHCI/OHCI against nsc-ircc on laptop.
Thanks to Martin for additional testing and feedback.

* Receiver:
	- changed from interrupt to bulk URB.  Queue's one bulk
	  urb per USB tick (1ms).
	- FIR unpack now uses get_unaligned and cpu32_le
	  instead of explicit shifts
	- FIR unpack copies small frames
* Transmitter:
	- pack data into io buffer.  Since irda is half duplex
	  can use same buffer for transmit and receive.
	- use xchange and wait_event for synchronization
* Other:
	- use USB format messages rather than IRDA (ugly)
	- clean up USB startup
	- reset device on network open to clear up stuck state
	- handle FIFO errors
	- disconnect cleanup (from viro)
	- don't DMA onto stack when reading fifo status