This small addition to the core simplifies code in the drivers and makes
them more robust when handling shared IRQs.
Signed-off-by: Alessandro Zummo <a.zummo@towertech.it>
Cc: Alexander Shiyan <shc_work@mail.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>