input: Move the xkb fields from weston_seat to weston_keyboard

XKB integration is a keyboard feature and should as such be kept track
of in the keyboard struct.

Signed-off-by: Jonas Ådahl <jadahl@gmail.com>
diff --git a/src/text-backend.c b/src/text-backend.c
index 107ccd6..59a8b94 100644
--- a/src/text-backend.c
+++ b/src/text-backend.c
@@ -598,8 +598,8 @@
 	context->keyboard = cr;
 
 	wl_keyboard_send_keymap(cr, WL_KEYBOARD_KEYMAP_FORMAT_XKB_V1,
-				seat->xkb_info->keymap_fd,
-				seat->xkb_info->keymap_size);
+				keyboard->xkb_info->keymap_fd,
+				keyboard->xkb_info->keymap_size);
 
 	if (keyboard->grab != &keyboard->default_grab) {
 		weston_keyboard_end_grab(keyboard);