drm/amdgpu: Using uninitialized value *size when calling amdgpu_vce_cs_reloc

mainline inclusion
from mainline-v6.10-rc1
commit 88a9a467c548d0b3c7761b4fd54a68e70f9c0944
category: bugfix
bugzilla: https://gitee.com/src-openeuler/kernel/issues/IAGSW7
CVE: CVE-2024-42228

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=88a9a467c548d0b3c7761b4fd54a68e70f9c0944



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

Initialize the size before calling amdgpu_vce_cs_reloc, such as case 0x03000001.
V2: To really improve the handling we would actually
   need to have a separate value of 0xffffffff.(Christian)

Signed-off-by: Jesse Zhang <jesse.zhang@amd.com>
Suggested-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Conflicts:
	drivers/gpu/drm/amd/amdgpu/amdgpu_vce.c
[adjust context conflicts]
Signed-off-by: Liu Chuang <liuchuang40@huawei.com>