mfd: fix the asic3 irq demux code

Wrong irq numbers were given to desc->handle_irq, which on some devices
caused endless loops (asic3_irq_demux calling itself, basically).

Signed-off-by: Philipp Zabel <philipp.zabel@gmail.com>
Signed-off-by: Samuel Ortiz <sameo@openedhand.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>