media: vidtv: mux: Add check and kfree for kstrdup

stable inclusion
from stable-v6.6.2
commit aae7598aff291d4d140be1355aa20930af948785
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I8IW7G

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=aae7598aff291d4d140be1355aa20930af948785



--------------------------------

[ Upstream commit 1fd6eb12642e0c32692924ff359c07de4b781d78 ]

Add check for the return value of kstrdup() and return the error
if it fails in order to avoid NULL pointer dereference.
Moreover, use kfree() in the later error handling in order to avoid
memory leak.

Fixes: c2f78f0c ("media: vidtv: psi: add a Network Information Table (NIT)")
Signed-off-by: Jiasheng Jiang <jiasheng@iscas.ac.cn>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>