staging:iio: lis3l02dq - separate entirely interrupt handling for thesholds...

staging:iio: lis3l02dq - separate entirely interrupt handling for thesholds from that for the datardy signal.

This removes the one and only real user of the rather complex event list management.
V3: More trivial rebase fixups.
V2: Trivial rebase fixup.

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