V4L/DVB (3332): XC3028 code marked with an special define option

- Current xc3028 support is still experimental, requiring more work to be
  sent to mainstream. So, it was marked inside some defines, in order to be
  removed by gentree.pl stript. Script also updated to remove it.

Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>