msdk: call vaExportSurfaceHandle() to get DMABuf FD
Compared to vaAcquireBufferHandle(), vaExportSurfaceHandle() may provide the handle details, so we needn't call vaDeriveImage().
Edited by Haihao Xiang
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Compared to vaAcquireBufferHandle(), vaExportSurfaceHandle() may provide the handle details, so we needn't call vaDeriveImage().