The interrupts schould be disabled until the driver
is ready and the IRQ function was registered.

Thanks to Bastian Friedrich  and Thomas Voegtle for spotting this.
Signed-off-by: Karsten Keil <kkeil@suse.de>
Signed-off-by: Bastian Friedrich <bastian@bastian-friedrich.de>
Signed-off-by: Thomas Voegtle <tv@lio96.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>