[PATCH] V4L: Fix hotplugging issues with saa7134

[PATCH] V4L: Fix hotplugging issues with saa7134

- Fixed issue with hotplugging and DMA sound (sound was lost when replugging
  a card)

- Added notifiers to main saa7134 module to let the sound sub-modules know
  when a card has been inserted or removed

Signed-off-by: Ricardo Cerqueira <v4l@cerqueira.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@brturbo.com.br>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>