staging:iio:adc:adt7410 move to current event handling

This device actually has a pair of interrupts. The code basically ignores
that and feeds them both to the same handlers.  I'm not sure if that is
the right thing to do, but the updated code should do exactly the same.

Signed-off-by: Jonathan Cameron <jic23@cam.ac.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>