tests: drivers: clock_control: nrf_clock_control: update fll16m

Update the nrf clock control test suite to not attempt to set the
removed closed loop mode of the fll16m clock.

Signed-off-by: Bjarki Arge Andreasen <bjarki.andreasen@nordicsemi.no>

Author: bjarki-andreasen

tests/drivers/clock_control/nrf_clock_control/src/main.c

@@ -41,11 +41,6 @@ const struct nrf_clock_spec test_clk_specs_fll16m[] = {
 		.accuracy = 20000,
 		.precision = NRF_CLOCK_CONTROL_PRECISION_DEFAULT,
 	},
-	{
-		.frequency = MHZ(16),
-		.accuracy = 5020,
-		.precision = NRF_CLOCK_CONTROL_PRECISION_DEFAULT,
-	},
 	{
 		.frequency = MHZ(16),
 		.accuracy = 30,