gpio: Fix error checking in the function device_pca957x_init

This fixes error checking in the function device_pca957x_init
to properly check and return error code values from the calls
to the function pca953x_write_regs if they fail as to properly
signal callers when a error occurs due a failure when writing
registers for this gpio based device.
Signed-off-by: Nicholas Krause <xerofoify@gmail.com>
Reviewed-by: Alexandre Courbot <acourbot@nvidia.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/gpio/gpio-pca953x.c

@@ -635,11 +635,15 @@ static int device_pca957x_init(struct pca953x_chip *chip, u32 invert)
 		memset(val, 0xFF, NBANK(chip));
 	else
 		memset(val, 0, NBANK(chip));
-	pca953x_write_regs(chip, PCA957X_INVRT, val);
+	ret = pca953x_write_regs(chip, PCA957X_INVRT, val);
+	if (ret)
+		goto out;
 
 	/* To enable register 6, 7 to control pull up and pull down */
 	memset(val, 0x02, NBANK(chip));
-	pca953x_write_regs(chip, PCA957X_BKEN, val);
+	ret = pca953x_write_regs(chip, PCA957X_BKEN, val);
+	if (ret)
+		goto out;
 
 	return 0;
 out: