[PATCH] irda: donauboe fixes, cleanups

- fix: toshoboe_invalid_dev() was recently removed, but not all callers
  were updated, causing the obvious linker error.  Remove caller,
  because the check (like the one removed) isn't used.

- fix: propagate request_irq() return value

- cleanup: remove void* casts

- cleanup: remove impossible ASSERTs

Signed-off-by: Jeff Garzik <jeff@garzik.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>