[nrf fromtree] drivers: clock_control: nrf: ignore XOTUNE-related events for now

New events from nrfx_clock driver are not utilized for now
by the clock_control, so should be ignored to avoid assertion.

Signed-off-by: Nikodem Kastelik <nikodem.kastelik@nordicsemi.no>
(cherry picked from commit 2692f16)

Author: nika-nordic

drivers/clock_control/clock_control_nrf.c

@@ -623,6 +623,11 @@ static void clock_event_handler(nrfx_clock_evt_type_t event)
 		}
 		break;
 	case NRFX_CLOCK_EVT_PLL_STARTED:
+#if NRF_CLOCK_HAS_XO_TUNE
+	case NRFX_CLOCK_EVT_XO_TUNED:
+	case NRFX_CLOCK_EVT_XO_TUNE_ERROR:
+	case NRFX_CLOCK_EVT_XO_TUNE_FAILED:
+#endif
 	{
 		/* unhandled event */
 		break;