xinput: ev DeviceKeyPress.device_id: add mask

xinput: ev DeviceKeyPress.device_id: add mask

for event DeviceKeyPress and derived ones:
add new 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#n1999
http://cgit.freedesktop.org/xorg/lib/libXi/tree/src/XExtInt.c#n534
http://cgit.freedesktop.org/xorg/xserver/tree/dix/eventconvert.c#n348
http://cgit.freedesktop.org/xorg/xserver/tree/Xi/exevents.c#n188

note:
this mask is missing in the following spec:
http://cgit.freedesktop.org/xorg/proto/inputproto/tree/specs/XIproto.txt#n2257