ppc/pmac_cpufreq: use poll_event*() interface

@@ -167,8 +167,6 @@ static unsigned int __pmac dfs_get_cpu_s
  */
 static int __pmac gpios_set_cpu_speed(int low_speed)
 {
-	int gpio;
-
 	/* If ramping up, set voltage first */
 	if (low_speed == 0) {
 		pmac_call_feature(PMAC_FTR_WRITE_GPIO, NULL, voltage_gpio, 0x05);

@@ -180,11 +178,8 @@ static int __pmac gpios_set_cpu_speed(in
 	pmac_call_feature(PMAC_FTR_WRITE_GPIO, NULL, frequency_gpio,
 			  low_speed ? 0x04 : 0x05);
 	udelay(200);
-	do {
-		set_current_state(TASK_UNINTERRUPTIBLE);
-		schedule_timeout(1);
-		gpio = pmac_call_feature(PMAC_FTR_READ_GPIO, NULL, slew_done_gpio, 0);
-	} while((gpio & 0x02) == 0);
+	/* check every millisecond until true */
+	poll_event(((pmac_call_feature(PMAC_FTR_READ_GPIO, NULL, slew_done_gpio, 0) & 0x02) != 0), 1);
 
 	/* If ramping down, set voltage last */
 	if (low_speed == 1) {