compositor-drm, evdev: don't crash on missing keyboard

Weston's notify_keyboard_focus_*() assume that a keyboard is present, if
they are called. With evdev, there might not always be a keyboard.

Also clean up the variable definition in evdev_notify_keyborad_focus().
I read that function through many times and finally had to grep where
does 'all_keys' come from.

Signed-off-by: Pekka Paalanen <ppaalanen@gmail.com>

src/compositor-drm.c

@@ -2012,7 +2012,8 @@ evdev_remove_devices(struct weston_seat *seat_base)
 	wl_list_for_each_safe(device, next, &seat->devices_list, link)
 		evdev_input_device_destroy(device);
 
-	notify_keyboard_focus_out(&seat->base.seat);
+	if (seat->base.seat.keyboard)
+		notify_keyboard_focus_out(&seat->base.seat);
 }
 
 static void

src/evdev.c

@@ -561,10 +561,14 @@ evdev_notify_keyboard_focus(struct weston_seat *seat,
 	struct evdev_input_device *device;
 	struct wl_array keys;
 	unsigned int i, set;
-	char evdev_keys[(KEY_CNT + 7) / 8], all_keys[(KEY_CNT + 7) / 8];
+	char evdev_keys[(KEY_CNT + 7) / 8];
+	char all_keys[(KEY_CNT + 7) / 8];
 	uint32_t *k;
 	int ret;
 
+	if (!seat->seat.keyboard)
+		return;
+
 	memset(all_keys, 0, sizeof all_keys);
 	wl_list_for_each(device, evdev_devices, link) {
 		memset(evdev_keys, 0, sizeof evdev_keys);