media: venus: change the default value of GOP size

When the client doesn't explicitly set any GOP size, current
default value is low and overshoots bitrate beyond  tolerance.
Hence default value is modified so as to have intra period of 1sec.

Signed-off-by: Malathi Gottam <mgottam@codeaurora.org>
Acked-by: Stanimir Varbanov <stanimir.varbanov@linaro.org>
Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>