tests: kernel: timer: timer_behavior: Fix max_stddev calculation

max_stddev calculation was previously patched to be more at least
1 system clock cycle to cover for platforms that use higher frequency
system clock (32kHz). On that platform (nRF52) system clock frequency
was the same as tick frequency but on nRF54x that is no longer true.
Initially, the intention was to use 1 system tick and not cycle.
Fixing it now.

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

Author: nordic-krch

tests/kernel/timer/timer_behavior/src/jitter_drift.c

@@ -237,8 +237,8 @@ static void do_test_using(void (*sample_collection_fn)(void), const char *mechan
 		- expected_time_drift_us;
 	double time_diff_us_abs = time_diff_us >= 0.0 ? time_diff_us : -time_diff_us;
 
-	/* If max stddev is lower than a single clock cycle then round it up. */
-	uint32_t max_stddev = MAX(k_cyc_to_us_ceil32(1), CONFIG_TIMER_TEST_MAX_STDDEV);
+	/* If max stddev is lower than a single clock tick then round it up. */
+	uint32_t max_stddev = MAX(k_ticks_to_us_ceil32(1), CONFIG_TIMER_TEST_MAX_STDDEV);
 
 	TC_PRINT("timer clock rate %u, kernel tick rate %d\n",
 		 sys_clock_hw_cycles_per_sec(), CONFIG_SYS_CLOCK_TICKS_PER_SEC);