drm/amdgpu/vcn: reset fw_shared under SRIOV

- The previous patch only considered the case for baremetal
  and is not applicable for SRIOV code path. We also need to
  init fw_share for SRIOV VF

Fixes: 928cd772 ("drm/amdgpu/vcn: reset fw_shared when VCPU buffers corrupted on vcn v4.0.3")
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Bokun Zhang <bokun.zhang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>