PM / OPP: Move error message to debug level

[ Upstream commit 035ed07208dc501d023873447113f3f178592156 ]

On some i.MX6 platforms which do not have speed grading
check, opp table will not be created in platform code,
so cpufreq driver prints the following error message:

cpu cpu0: dev_pm_opp_get_opp_count: OPP table not found (-19)

However, this is not really an error in this case because the
imx6q-cpufreq driver first calls dev_pm_opp_get_opp_count()
and if it fails, it means that platform code does not provide
OPP and then dev_pm_opp_of_add_table() will be called.

In order to avoid such confusing error message, move it to
debug level.

It is up to the caller of dev_pm_opp_get_opp_count() to check its
return value and decide if it will print an error or not.

Signed-off-by: Fabio Estevam <fabio.estevam@nxp.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/base/power/opp/core.c

@@ -296,7 +296,7 @@ int dev_pm_opp_get_opp_count(struct device *dev)
 	opp_table = _find_opp_table(dev);
 	if (IS_ERR(opp_table)) {
 		count = PTR_ERR(opp_table);
-		dev_err(dev, "%s: OPP table not found (%d)\n",
+		dev_dbg(dev, "%s: OPP table not found (%d)\n",
 			__func__, count);
 		return count;
 	}