[nrf fromlist] drivers: pwm: nrf: fix nrfx instance being zeroed on suspend

PWM driver clears its runtime state on each suspend event.
However, since nrfx 4.0 integration nrfx driver instance is part
of the runtime state structure, so clear action must be limited.

Upstream PR #: 100309

Signed-off-by: Nikodem Kastelik <[email protected]>
(cherry picked from commit ace550c)

Author: nika-nordic

drivers/pwm/pwm_nrfx.c

@@ -354,7 +354,11 @@ static int pwm_suspend(const struct device *dev)
 	while (!nrfx_pwm_stopped_check(&data->pwm)) {
 	}
 
-	memset(dev->data, 0, sizeof(struct pwm_nrfx_data));
+	/* Explicitly clear driver state that might be invalid after subsequent resume. */
+	data->period_cycles = 0;
+	data->pwm_needed = 0;
+	data->prescaler = 0;
+	data->stop_requested = 0;
 	(void)pinctrl_apply_state(config->pcfg, PINCTRL_STATE_SLEEP);
 
 	return 0;