drivers: adxl362: use Kconfig for interrupt mode

Commit 11295c19 added Kconfig options for interrupt mode, but then hard
coded the interrupt mode. This commit uses the Kconfig option to set
the interrupt mode.

Applications expecting the interrupt mode to be something other than
the default will need to be updated.

Signed-off-by: Brett Witherspoon <spoonb@cdspooner.com>