media: vicodec: Add num_planes field to v4l2_fwht_pixfmt_info

Add the field 'num_planes' to 'v4l2_fwht_pixfmt_info' struct.

Signed-off-by: Dafna Hirschfeld <dafna3@gmail.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>