drm/amdkfd: Check for null pointer after calling kmemdup

stable inclusion
from stable-v6.0.14
commit abfaf0ee
category: bugfix
bugzilla: https://gitee.com/src-openeuler/kernel/issues/I6694U
CVE: CVE-2022-3108

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=abfaf0eee97925905e742aa3b0b72e04a918fa9e



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

As the possible failure of the allocation, kmemdup() may return NULL
pointer.
Therefore, it should be better to check the 'props2' in order to prevent
the dereference of NULL pointer.

Fixes: 3a87177e ("drm/amdkfd: Add topology support for dGPUs")
Signed-off-by: Jiasheng Jiang <jiasheng@iscas.ac.cn>
Reviewed-by: Felix Kuehling <Felix.Kuehling@amd.com>
Signed-off-by: Felix Kuehling <Felix.Kuehling@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Ren Zhijie <renzhijie2@huawei.com>
Reviewed-by: songping yu <yusongping@huawei.com>
Reviewed-by: Chen Hui <judy.chenhui@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>