pinctrl: samsung: Detect and handle unsupported configuration types

This patch modifies the pinctrl-samsung driver to detect when width of a
bit field is set to zero (which means that such configuraton type is not
supported) and return an error instead of trying to modify an inexistent
register.
Signed-off-by: Tomasz Figa <t.figa@samsung.com>
Reviewed-by: Kyungmin Park <kyungmin.park@samsung.com>
Acked-by: Thomas Abraham <thomas.abraham@linaro.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/pinctrl/pinctrl-samsung.c

@@ -391,6 +391,9 @@ static int samsung_pinconf_rw(struct pinctrl_dev *pctldev, unsigned int pin,
 		return -EINVAL;
 	}
 
+	if (!width)
+		return -EINVAL;
+
 	mask = (1 << width) - 1;
 	shift = pin_offset * width;
 	data = readl(reg_base + cfg_reg);