drivers: timer: nrf_rtc_timer: Prevent prolonged timeout setting

CC setting algorithm is handling a case when CC is too soon (next
tick from now). It was setting CC to one tick further in the future
if that was detected. Step was repeated if counter incremented during
setting CC and CC was behind the counter because of risk of setting
CC too late. In certain scenarios we might spend a lot of time in
that loop, especially if optimization is turned off. Test shown that
loop was executed dozens of time (up. to 700us). To prevent
prolonged execution whenever CC setting fails we set CC to one more
tick further in future.

Signed-off-by: Krzysztof Chruscinski <krzysztof.chruscinski@nordicsemi.no>