[media] mceusb: command/response updates from MS docs

I was recently pointed to the document titled
Windows-Media-Center-RC-IR-Collection-Green-Button-Specification-03-08-2011-V2.pdf
which as of this writing, is publicly available from
download.microsoft.com. It covers a LOT of the gaps in the mceusb
driver, which to this point, was written almost entirely by
reverse-engineering. First up, I'm updating the defines for all the MCE
commands and responses to match their names in the spec. More to come...

Signed-off-by: Jarod Wilson <jarod@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>