media: input/touchscreen/sur40: use COLORSPACE_RAW

This driver set the colorspace to SRGB, but that makes no sense for
a touchscreen. Use RAW instead. This also ensures consistency with the
v4l_pix_format_touch() call that's used in v4l2-ioctl.c.

Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Acked-by: Florian Echtler <floe@butterbrot.org>
Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>