xinput: ev DeviceStateNotify.device_id: mask

xinput: ev DeviceStateNotify.device_id: mask

add mask "MoreEventsMask" to field "device_id"

V2: patch revised according to suggestion from Peter Harris:
* use "altmask" instead of "mask"
  because all the legal values of device_id are not described
  by the <bit> elements of MoreEventsMask.

spec and code:
http://cgit.freedesktop.org/xorg/lib/libXi/tree/specs/encoding.xml#n2214
http://cgit.freedesktop.org/xorg/xserver/tree/dix/enterleave.c#n725

note:
this mask is missing in the following spec:
http://cgit.freedesktop.org/xorg/proto/inputproto/tree/specs/XIproto.txt#n2395