gpio: pca953x: Fix register reading past 8th GPIO

A bug in the pca953x driver prevents correct reading of GPIO input
values beyond the 8th GPIO; all values are reported as zero. Setting of
GPIO output values is not affected.

This patch fixes the reading behavior.

Signed-off-by: Mario Six <mario.six@gdsys.cc>
Reviewed-by: Peng Fan <van.freenix@gmail.com>
Acked-by: Simon Glass <sjg@chromium.org>

drivers/gpio/pca953x_gpio.c

@@ -148,11 +148,13 @@ static int pca953x_get_value(struct udevice *dev, unsigned offset)
 	int ret;
 	u8 val = 0;
 
+	int off = offset % BANK_SZ;
+
 	ret = pca953x_read_single(dev, PCA953X_INPUT, &val, offset);
 	if (ret)
 		return ret;
 
-	return (val >> offset) & 0x1;
+	return (val >> off) & 0x1;
 }
 
 static int pca953x_set_value(struct udevice *dev, unsigned offset,