media: allegro: remove cpb_size and gop_size from channel

The cpb_size and the gop_size are straight copies of the values in the
v4l2-ctrls. To avoid this duplication, directly get the values from the
v4l2-ctrls and remove the copies.

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>