media: allegro: fix type of gop_length in channel_create message

media: allegro: fix type of gop_length in channel_create message

The gop_length field is actually only u16 and there are two more u8
fields in the message:

- the number of consecutive b-frames
- frequency of golden frames

Fix the message and thus fix the configuration of the GOP length.

Signed-off-by: Michael Tretter <m.tretter@pengutronix.de>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>