pinctrl: use dev_err() to show message in pinctrl_register_one_pin()

Use dev_err() rather than pr_err() to display the error message.
(Besides, dev_err() is already used 7 lines below in this function.)

Also, drop the redundant information "on %s" because dev_err() shows
which device the message is related to.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/pinctrl/core.c

@@ -231,8 +231,7 @@ static int pinctrl_register_one_pin(struct pinctrl_dev *pctldev,
 
 	pindesc = pin_desc_get(pctldev, number);
 	if (pindesc != NULL) {
-		pr_err("pin %d already registered on %s\n", number,
-		       pctldev->desc->name);
+		dev_err(pctldev->dev, "pin %d already registered\n", number);
 		return -EINVAL;
 	}