PM / Domains: Return early for all errors in _genpd_power_off()

It is strange to only return early for -EBUSY state and left other
errors to be still measured execution time.

As for error cases, the elapsed_ns computed actually is not quite
accurate and meaningful for governor to use. So let's simply return
for all error cases.
Signed-off-by: NDong Aisheng <aisheng.dong@nxp.com>
Reviewed-by: NUlf Hansson <ulf.hansson@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/base/power/domain.c

@@ -457,19 +457,19 @@ static int _genpd_power_off(struct generic_pm_domain *genpd, bool timed)
 
 	time_start = ktime_get();
 	ret = genpd->power_off(genpd);
-	if (ret == -EBUSY)
+	if (ret)
 		return ret;
 
 	elapsed_ns = ktime_to_ns(ktime_sub(ktime_get(), time_start));
 	if (elapsed_ns <= genpd->states[state_idx].power_off_latency_ns)
-		return ret;
+		return 0;
 
 	genpd->states[state_idx].power_off_latency_ns = elapsed_ns;
 	genpd->max_off_time_changed = true;
 	pr_debug("%s: Power-%s latency exceeded, new value %lld ns\n",
 		 genpd->name, "off", elapsed_ns);
 
-	return ret;
+	return 0;
 }
 
 /**