mfd/gpio: Move HTC GPIO driver to GPIO subsystem

The HTC GPIO driver is a pure GPIO driver and I just can not
see what it is doing inside MFD. Let's just move it to GPIO
and take this opportunity to move the platform data to
<linux/platform_data/gpio-htc-egpio.h>

Cc: arm@kernel.org
Cc: Russell King <linux@armlinux.org.uk>
Acked-by: Lee Jones <lee.jones@linaro.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index 98dd47a..03be200 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -848,6 +848,14 @@
 	  This driver can also be built as a module. If so, the module
 	  will be called gpio-dln2.
 
+config HTC_EGPIO
+	bool "HTC EGPIO support"
+	depends on GPIOLIB && ARM
+	help
+	    This driver supports the CPLD egpio chip present on
+	    several HTC phones.  It provides basic support for input
+	    pins, output pins, and irqs.
+
 config GPIO_JANZ_TTL
 	tristate "Janz VMOD-TTL Digital IO Module"
 	depends on MFD_JANZ_CMODIO