drivers: timer: Fix nRF RTC timer _timer_cycle_get_32
drivers: timer: Fix nRF RTC timer _timer_cycle_get_32

Fix nRF RTC timer from returning more than actual cycles
in _timer_cycle_get_32, under race condition when ISR
announces to kernel.

Jira: ZEP-2229

Signed-off-by: Vinayak Kariappa Chettimada <e780c9f87dc729ad454f47292ad82c8652353064@nordicsemi.no>

bigdinotech/zephyr,bigdinotech/zephyr,bigdinotech/zephyr,bigdinotech/zephyr,bigdinotech/zephyr