hwmon: (acpi_power_meter) Change log level for 'unsafe software power cap'

At boot time, the acpi_power_meter driver logs the following error level
message: "Ignoring unsafe software power cap". Having read about it from
a few sources, it seems that the error message can be quite misleading.

While the message can imply that Linux is ignoring the fact that the
system is operating in potentially dangerous conditions, the truth is
the driver found an ACPI_PMC object that supports software power
capping. The driver simply decides not to use it, perhaps because it
doesn't support the object.

The best solution is probably changing the log level from error to warning.
All sources I have found, regarding the error, have downplayed its
significance. There is not much of a reason for it to be on error level,
while causing potential confusions or misinterpretations.
Signed-off-by: Wang Shenran <shenran268@gmail.com>
Link: https://lore.kernel.org/r/20190724080110.6952-1-shenran268@gmail.comSigned-off-by: Guenter Roeck <linux@roeck-us.net>

drivers/hwmon/acpi_power_meter.c

@@ -681,8 +681,8 @@ static int setup_attrs(struct acpi_power_meter_resource *resource)
 
 	if (resource->caps.flags & POWER_METER_CAN_CAP) {
 		if (!can_cap_in_hardware()) {
-			dev_err(&resource->acpi_dev->dev,
-				"Ignoring unsafe software power cap!\n");
+			dev_warn(&resource->acpi_dev->dev,
+				 "Ignoring unsafe software power cap!\n");
 			goto skip_unsafe_cap;
 		}