gpio/pcf857x: Copy i2c_device_id from old pcf8574 driver

The deprecated pcf8574 driver is going to be removed. Make sure the
replacement driver inherits all i2c_device_ids for a smooth transition.

Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
Cc: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Jean Delvare <khali@linux-fr.org>

drivers/gpio/pcf857x.c

@@ -28,6 +28,7 @@
 
 static const struct i2c_device_id pcf857x_id[] = {
 	{ "pcf8574", 8 },
+	{ "pcf8574a", 8 },
 	{ "pca8574", 8 },
 	{ "pca9670", 8 },
 	{ "pca9672", 8 },