iio: light: adux1020: write_event_config: use local variable for interrupt value

iio: light: adux1020: write_event_config: use local variable for interrupt value

state parameter is currently an int, but it is actually a boolean.
iio_ev_state_store is actually using kstrtobool to check user input,
then gives the converted boolean value to write_event_config.  The code
in adux1020_write_event_config re-uses state parameter to store an
integer value. To prepare for updating the write_event_config signature
to use a boolean for state, introduce a new local int variable.

Signed-off-by: Julien Stephan <jstephan@baylibre.com>
Link: https://patch.msgid.link/20241031-iio-fix-write-event-config-signature-v2-6-2bcacbb517a2@baylibre.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>