[PATCH] dvb: core: dmxdev cleanups

- remove void casts
- not necessary to set filter state twice to STATE_FREE during
  dvb_dmxdev_init()

Signed-off-by: Peter Beutner <p.beutner@gmx.net>
Signed-off-by: Johannes Stezenbach <js@linuxtv.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>