libinput-device: Remove unnecessary function call

When we handle pointer button events, we already retrieve the button
state at the top of this function, so there is no real need to call
the same function again as we can just reuse the 'button_state'
variable that we have above.

Signed-off-by: Chris Michael <cpmichael@osg.samsung.com>
Reviewed-by: Bryce Harrington <bryce@osg.samsung.com>
diff --git a/src/libinput-device.c b/src/libinput-device.c
index 99b2916..78b0ac9 100644
--- a/src/libinput-device.c
+++ b/src/libinput-device.c
@@ -154,7 +154,8 @@
 	notify_button(device->seat,
 		      libinput_event_pointer_get_time(pointer_event),
 		      libinput_event_pointer_get_button(pointer_event),
-		      libinput_event_pointer_get_button_state(pointer_event));
+                      button_state);
+
 	return true;
 }