[msm7k] fix warning in gpio.c
diff --git a/platform/msm7k/gpio.c b/platform/msm7k/gpio.c
index ba82a8c..8968921 100644
--- a/platform/msm7k/gpio.c
+++ b/platform/msm7k/gpio.c
@@ -196,6 +196,7 @@
 	} else {
 		writel(v & (~b), r->oe);
 	}
+	return 0;
 }
 
 void gpio_set(unsigned n, unsigned on)