PM / OPP: Use ERR_CAST instead of ERR_PTR(PTR_ERR())

Use ERR_CAST inlined function instead of ERR_PTR(PTR_ERR(...))

[The semantic patch that makes this change is available
 in scripts/coccinelle/api/err_cast.cocci.

 More information about semantic patching is available at
 http://coccinelle.lip6.fr/]
Signed-off-by: NThomas Meyer <thomas@m3y3r.de>
Signed-off-by: NRafael J. Wysocki <rjw@sisk.pl>

drivers/base/power/opp.c

@@ -669,7 +669,7 @@ struct srcu_notifier_head *opp_get_notifier(struct device *dev)
 	struct device_opp *dev_opp = find_device_opp(dev);
 
 	if (IS_ERR(dev_opp))
-		return ERR_PTR(PTR_ERR(dev_opp)); /* matching type */
+		return ERR_CAST(dev_opp); /* matching type */
 
 	return &dev_opp->head;
 }