V4L/DVB (4057): Cx88: IR remote support for DTV2000H

Adds support for the Y0400052 remote supplied with this card.
In addition to adding a number of buttons to the current winfast definition,
it enables all the keys currently masked out with #ifdef 0.

It is supplied separately as it remaps two keys from the current definition,
The teletext button now sends KEY_TEXT instead of KEY_SUBTITLE, as that
keycode is used by the subtitle button.
KEY_BACK was changed to KEY_LAST to group it with KEY_NEXT.

Other then that the keys don't overlap, so this should support several
different versions of the Leadtek remotes.

Signed-off-by: Malcolm Valentine <farkit@iinet.net.au>
Signed-off-by: Michael Krufky <mkrufky@linuxtv.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>