egl/android: handle multi-fd native windows

egl/android: handle multi-fd native windows

We can hit multi-fd EGL_NATIVE_BUFFER_ANDROID case when the native
android buffer is YUV.  So we need to handle that.

Currently this went unnoticed because, even though we have two or
three fd's for YUV native android buffers, they all reference the
same backing buffer.  But we really shouldn't rely on that.

Signed-off-by: Rob Clark <robdclark@chromium.org>
Reviewed-by: Eric Engestrom <eric@engestrom.ch>
Reviewed-by: Kristian H. Kristensen <hoegsberg@google.com>
Reviewed-by: Eric Anholt <eric@anholt.net>