share/cairo-util: Use wl_pointer_button_state enum directly

This silences two warnings:

clients/window.c:2450:20: warning: implicit conversion from enumeration
type 'enum wl_pointer_button_state' to different enumeration type 'enum
frame_button_state' [-Wenum-conversion]
                                              button, state);
                                                      ^~~~~

clients/window.c:2453:15: warning: implicit conversion from enumeration
type 'enum wl_pointer_button_state' to different enumeration type 'enum
frame_button_state' [-Wenum-conversion]
                                                button, state);
                                                        ^~~~~

Warning produced by Clang 3.8.

Signed-off-by: Quentin Glidic <sardemff7+git@sardemff7.net>
Reviewed-by: Giulio Camuffo <giuliocamuffo@gmail.com>
diff --git a/libweston/compositor-wayland.c b/libweston/compositor-wayland.c
index c223baa..0375a11 100644
--- a/libweston/compositor-wayland.c
+++ b/libweston/compositor-wayland.c
@@ -1363,22 +1363,17 @@
 static void
 input_handle_button(void *data, struct wl_pointer *pointer,
 		    uint32_t serial, uint32_t time, uint32_t button,
-		    uint32_t state_w)
+		    enum wl_pointer_button_state state)
 {
 	struct wayland_input *input = data;
-	enum wl_pointer_button_state state = state_w;
-	enum frame_button_state fstate;
 	enum theme_location location;
 
 	if (!input->output)
 		return;
 
 	if (input->output->frame) {
-		fstate = state == WL_POINTER_BUTTON_STATE_PRESSED ?
-			FRAME_BUTTON_PRESSED : FRAME_BUTTON_RELEASED;
-
 		location = frame_pointer_button(input->output->frame, input,
-						button, fstate);
+						button, state);
 
 		if (frame_status(input->output->frame) & FRAME_STATUS_MOVE) {