media: venus: vdec: return parsed crop information from stream

Per the stateful codec specification, VIDIOC_G_SELECTION with a target
of V4L2_SEL_TGT_COMPOSE is supposed to return the crop area of capture
buffers containing the decoded frame. Until now the driver did not get
that information from the firmware and just returned the dimensions of
CAPTURE buffers.

The firmware unfortunately does not always provide the crop information
from the stream ; also make sure to detect when that happens and
fallback to providing the coded size in these cases.

Signed-off-by: Alexandre Courbot <acourbot@chromium.org>
Signed-off-by: Stanimir Varbanov <stanimir.varbanov@linaro.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>