MIPS: AR7: Initialize GPIO earlier

In order to detect the Titan variant, we must initialize GPIOs earlier since
detection relies on some GPIO values to be set.

Signed-off-by: Florian Fainelli <florian@openwrt.org>
Patchwork: http://patchwork.linux-mips.org/patch/1562/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

---
diff --git a/arch/mips/include/asm/mach-ar7/ar7.h b/arch/mips/include/asm/mach-ar7/ar7.h
index 483ffea..ddb413e 100644
--- a/arch/mips/include/asm/mach-ar7/ar7.h
+++ b/arch/mips/include/asm/mach-ar7/ar7.h
@@ -161,4 +161,6 @@
 	msleep(20);
 }
 
+int __init ar7_gpio_init(void);
+
 #endif /* __AR7_H__ */