Revert "drm/amdgpu/vcn: add shared memory restore after wake up from sleep."

This reverts commit 21b704d7.
To merge vcn firmware shared memory bo into vcn vcpu bo.

Signed-off-by: James Zhu <James.Zhu@amd.com>
Reviewed-by: Leo Liu <leo.liu@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>