staging: iio: lis3l02dq - incorrect ws used in container of call.

The word oops comes to mind.  Original patch to merge the two work queues
in here (prior to Greg taking them into staging) changed the top half to
only use one of them and the bottom half to assume it was the other.

Currently causes a NULL pointer dereference if you enable any of the events
on an lis3l02dq. Just goes to show I need a few more regression tests.

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