pinctrl: bcm281xx: Add missing assignment in bcm21664_pinctrl_lock_all()

The next line checks if this regmap_write() failed, but it doesn't
work because the assignment was accidentally left out.  Add the
assignment.

Fixes: 60d6976 ("pinctrl: bcm281xx: Add support for BCM21664 pinmux")
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Acked-by: Artur Weber <aweber.kernel@gmail.com>
Reviewed-by: Florian Fainelli <florian.fainelli@broadcom.com>
Link: https://lore.kernel.org/dfc15d59-7fa9-4f96-aacb-37c3df6d420d@stanley.mountain
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

Author: Dan Carpenter

drivers/pinctrl/bcm/pinctrl-bcm281xx.c

@@ -1498,8 +1498,8 @@ static int bcm21664_pinctrl_lock_all(struct bcm281xx_pinctrl_data *pdata)
 				rc);
 			return rc;
 		}
-		regmap_write(pdata->regmap, BCM21664_ACCESS_LOCK_OFFSET(i),
-			     0xffffffff);
+		rc = regmap_write(pdata->regmap, BCM21664_ACCESS_LOCK_OFFSET(i),
+				  0xffffffff);
 		if (rc) {
 			dev_err(pdata->dev, "Failed to write access lock: %d\n",
 				rc);