tests: drivers: clock_control_api: longer startup time for RC

Increasing startup time for LFCLK RC. Setting high stable
value as detailed characteristics are not yet available.

Signed-off-by: Michał Stasiak <[email protected]>

Author: mstasiaknordic

tests/zephyr/drivers/clock_control/clock_control_api/nrf_lfclk_rc.conf

@@ -1,3 +1,4 @@
 CONFIG_ZTEST=y
 CONFIG_CLOCK_CONTROL_NRF_K32SRC_RC=y
 CONFIG_CLOCK_CONTROL_NRF_K32SRC_RC_CALIBRATION=n
+CONFIG_TEST_NRF_HF_STARTUP_TIME_US=1000