media: v4l2-ioctl.c: add V4L2_PIX_FMT_FWHT_STATELESS to v4l_fill_fmtdesc

Add V4L2_PIX_FMT_FWHT_STATELESS to the list of pixelformats that
v4l_fill_fmtdesc() understands.

Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>