pinctrl: sh-pfc: Use reg_width instead of reg as sentinel

All other loops over sh_pfc_soc_info.data_regs[] use
pinmux_data_reg.regwidth as the sentinel, which is safer as zero is
never a valid regwidth value (reg could be zero if we start using it to
store an offset).
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/pinctrl/sh-pfc/gpio.c

@@ -84,7 +84,7 @@ static void gpio_setup_data_reg(struct sh_pfc_chip *chip, unsigned idx)
 	unsigned int bit;
 	unsigned int i;
 
-	for (i = 0, dreg = pfc->info->data_regs; dreg->reg; ++i, ++dreg) {
+	for (i = 0, dreg = pfc->info->data_regs; dreg->reg_width; ++i, ++dreg) {
 		for (bit = 0; bit < dreg->reg_width; bit++) {
 			if (dreg->enum_ids[bit] == pin->enum_id) {
 				gpio_pin->dreg = i;