[media] cxusb: dvico remotes are nec

Adjust the keymap to use the correct nec scancodes, and adjust the
rc driver to output the correct nec scancodes.

Now the keymap can be used with any nec receiver, and the rc device
should work with any nec keymap.

Tested-by: Vincent McIntyre <vincent.mcintyre@gmail.com>
Signed-off-by: Sean Young <sean@mess.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>