ssb: add GPIO driver

Register a GPIO driver to access the GPIOs provided by the chip.
The GPIOs of the SoC should always start at 0 and the other GPIOs could
start at a random position. There is just one SoC in a system and when
they start at 0 the number is predictable.

Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>
Patchwork: http://patchwork.linux-mips.org/patch/4591
Acked-by: Florian Fainelli <florian@openwrt.org>
diff --git a/drivers/ssb/Kconfig b/drivers/ssb/Kconfig
index 42cdaa9..ff3c8a2 100644
--- a/drivers/ssb/Kconfig
+++ b/drivers/ssb/Kconfig
@@ -160,4 +160,13 @@
 
 	  If unsure, say N
 
+config SSB_DRIVER_GPIO
+	bool "SSB GPIO driver"
+	depends on SSB
+	select GPIOLIB
+	help
+	  Driver to provide access to the GPIO pins on the bus.
+
+	  If unsure, say N
+
 endmenu