layer-shell: fix type of margins

These currently use uint32_t while they are an int32_t in the protocol.

include/wlr/types/wlr_layer_shell_v1.h

@@ -58,7 +58,7 @@ struct wlr_layer_surface_v1_state {
 	uint32_t anchor;
 	int32_t exclusive_zone;
 	struct {
-		uint32_t top, right, bottom, left;
+		int32_t top, right, bottom, left;
 	} margin;
 	enum zwlr_layer_surface_v1_keyboard_interactivity keyboard_interactive;
 	uint32_t desired_width, desired_height;

types/wlr_layer_shell_v1.c

@@ -168,10 +168,10 @@ static void layer_surface_handle_set_margin(
 		return;
 	}
 
-	if (surface->current.margin.top == (uint32_t) top
-			&& surface->current.margin.right == (uint32_t) right
-			&& surface->current.margin.bottom == (uint32_t) bottom
-			&& surface->current.margin.left == (uint32_t) left) {
+	if (surface->current.margin.top == top
+			&& surface->current.margin.right == right
+			&& surface->current.margin.bottom == bottom
+			&& surface->current.margin.left == left) {
 		surface->pending.committed &= ~WLR_LAYER_SURFACE_V1_STATE_MARGIN;
 	} else {
 		surface->pending.committed |= WLR_LAYER_SURFACE_V1_STATE_MARGIN;