cpuidle: Remove redundant check in cpuidle_switch_governor()

gov has already been NULL checked at the beginning of
cpuidle_switch_governor, so remove redundant check.

While at it, use pr_info() instead printk() to address the following
checkpatch warning:

WARNING: Prefer [subsystem eg: netdev]_info([subsystem]dev, ... then
dev_info(dev, ... then pr_info(...  to printk(KERN_INFO ...
Signed-off-by: Yu Liao <liaoyu15@huawei.com>
[ rjw: Subject and changelog edits, added empty line after if () ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/cpuidle/governor.c

@@ -63,12 +63,11 @@ int cpuidle_switch_governor(struct cpuidle_governor *gov)
 
 	cpuidle_curr_governor = gov;
 
-	if (gov) {
-		list_for_each_entry(dev, &cpuidle_detected_devices, device_list)
-			cpuidle_enable_device(dev);
-		cpuidle_install_idle_handler();
-		printk(KERN_INFO "cpuidle: using governor %s\n", gov->name);
-	}
+	list_for_each_entry(dev, &cpuidle_detected_devices, device_list)
+		cpuidle_enable_device(dev);
+
+	cpuidle_install_idle_handler();
+	pr_info("cpuidle: using governor %s\n", gov->name);
 
 	return 0;
 }