Remove unnecessary args from GPIO functions

Now that gpio_init() and read_gpios() doesn't use
D-Bus, they don't need the D-Bus connection parameter.

Change-Id: Id7f3ee6547bed7c0c0eed5d75cba2d6ff239d0fa
Signed-off-by: Matt Spinler <spinler@us.ibm.com>
diff --git a/pwrbutton/button_power_obj.c b/pwrbutton/button_power_obj.c
index 58a9cad..2c3d32f 100644
--- a/pwrbutton/button_power_obj.c
+++ b/pwrbutton/button_power_obj.c
@@ -113,7 +113,7 @@
 	// get gpio device paths
 	int rc = GPIO_OK;
 	do {
-		rc = gpio_init(connection,&gpio_button);
+		rc = gpio_init(&gpio_button);
 		gpio_inits_done();
 		if(rc != GPIO_OK) { break; }
 		rc = gpio_open_interrupt(&gpio_button,on_button_interrupt,object);