media: staging: media: zoran: move videodev alloc

stable inclusion
from stable-v5.10.110
commit bd01629315ffd5b63da91d0bd529a77d30e55028
bugzilla: https://gitee.com/openeuler/kernel/issues/I574AL

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=bd01629315ffd5b63da91d0bd529a77d30e55028



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[ Upstream commit 82e3a496 ]

Move some code out of zr36057_init() and create new functions for handling
zr->video_dev. This permit to ease code reading and fix a zr->video_dev
memory leak.

Signed-off-by: Corentin Labbe <clabbe@baylibre.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Yu Liao <liaoyu15@huawei.com>
Reviewed-by: Wei Li <liwei391@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>