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

commit 88a9a467c548d0b3c7761b4fd54a68e70f9c0944 upstream.

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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Vamsi Krishna Brahmajosyula <vamsi-krishna.brahmajosyula@broadcom.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
(cherry picked from commit d35cf41c8eb5d9fe95b21ae6ee2910f9ba4878e8)
[Vegard: fix conflicts in context due to missing commit
 235943189db8ce05b888f48a04ded4448eebc408 ("drm/amdgpu: fix VCE buffer
 placement restrictions v2").]
Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com>