drivers: ds2484: Fix wrong early exit during suspend/resume
drivers: ds2484: Fix wrong early exit during suspend/resume

The sleep pin is optional and the driver checks for availability during
runtime. Currently the logic is inverted and therefore the driver exits
early if the pin is actually available. This pr fixes this behavior.

Also: Add `fallthrough` flags to switch/case

Signed-off-by: Caspar Friedrich <b69fdf08b699fe027a56448c8ef0f4830857c742@gmail.com>

finikorg/zephyr,galak/zephyr,zephyrproject-rtos/zephyr,finikorg/zephyr,galak/zephyr,zephyrproject-rtos/zephyr,zephyrproject-rtos/zephyr,galak/zephyr,galak/zephyr,zephyrproject-rtos/zephyr,finikorg/zephyr,finikorg/zephyr,zephyrproject-rtos/zephyr,galak/zephyr,finikorg/zephyr