drm/amdgpu: Fix uvd ib test timeout when use pre-allocated BO

drm/amdgpu: Fix uvd ib test timeout when use pre-allocated BO

Now we use same BO for create/destroy msg. So destroy will wait for the
fence returned from create to be signaled. The default timeout value in
destroy is 10ms which is too short.

Lets wait both fences with the specific timeout.

Signed-off-by: xinhui pan <xinhui.pan@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>