hwmon: lis3: Cleanup interrupt handling

Irqcfg moved to chip data instead of platform data.
This simplifies access in interrupt handler little bit.

Input device open and close functions set status for
interrupt threaded handler once.

Unnecessary check for interrupt source removed since
it is enough that active interrupt line indicates that
there was an interrupt.

Signed-off-by: Samu Onkalo <samu.p.onkalo@nokia.com>
Acked-by: Eric Piel <eric.piel@tremplin-utc.net>
Signed-off-by: Guenter Roeck <guenter.roeck@ericsson.com>