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/gpio-pca953x.c b/drivers/gpio/gpio-pca953x.c
index 019b23b..cede6f6 100644
--- a/drivers/gpio/gpio-pca953x.c
+++ b/drivers/gpio/gpio-pca953x.c
@@ -1,5 +1,5 @@
 /*
- *  PCA953x 4/8/16 bit I/O ports
+ *  PCA953x 4/8/16/24/40 bit I/O ports
  *
  *  Copyright (C) 2005 Ben Gardner <bgardner@wabtec.com>
  *  Copyright (C) 2007 Marvell International Ltd.