rtc-vp9: Fix to rcstats in vp9_spatial_svc_encoder
rtc-vp9: Fix to rcstats in vp9_spatial_svc_encoder

Fixes the rcstats for case when #spatial_layers = 1.

Change-Id: Ie28d99852033307bc4c69c7e738e1d4cab4e8cf5

webmproject/libvpx,ShiftMediaProject/libvpx,ShiftMediaProject/libvpx,webmproject/libvpx,ShiftMediaProject/libvpx,webmproject/libvpx,webmproject/libvpx,webmproject/libvpx,ShiftMediaProject/libvpx,ShiftMediaProject/libvpx,webmproject/libvpx