gpio: pca953x: Add devices to Kconfig help

The pca953x driver supports tca6424 (24-bit) and pca9505 (40-bit)
devices. They were the only supported devices not mentioned in the
Kconfig help.

Signed-off-by: Aaron Sierra <asierra@xes-inc.com>
Acked-by: Graeme Smecher <gsmecher@threespeedlogic.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index 2ca735f..69d1a90 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -476,6 +476,10 @@
 	  16 bits:	max7312, max7313, pca9535, pca9539, pca9555, pca9575,
 			tca6416
 
+	  24 bits:	tca6424
+
+	  40 bits:	pca9505
+
 config GPIO_PCA953X_IRQ
 	bool "Interrupt controller support for PCA953x"
 	depends on GPIO_PCA953X=y