skia: add compat SkBitmap::setConfig symbol

Required for older Samsung libtvout and HTC camera.tegra.

Change-Id: Icaae6ca01556553e57c3a194427093c59e0c5f65
skia: add compat SkImageDecoder::DecodeStream symbol

Required for older HTC camera.tegra.

Change-Id: Ic5114f04e037a74b9b4010af91b1fea06b5d75fd