d3d12: Initialize d3d12_video_encoder_references_manager_hevc::m_current_frame_idx.
Fix defect reported by Coverity Scan.
Uninitialized scalar field (UNINIT_CTOR) uninit_member: Non-static class member m_current_frame_idx is not initialized in this constructor nor in any functions that it calls.
Fixes: da11684e ("d3d12: Add HEVC Decode/Encode") Signed-off-by: Vinson Lee vlee@freedesktop.org