va: allocator: Fix translation of VADRMPRIMESurfaceDescriptor

va: allocator: Fix translation of VADRMPRIMESurfaceDescriptor

VADRMPRIMESurfaceDescriptor structure describes the offsets from the
point of view of the specific handle (DMABuf). While GstVideoInfo
(and the meta) describes offsets from the point of the view of the
GstBuffer, an aggregate of all the GstMemory (1 per handle).

This changes combined with [Mesa Fix](https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/16813)
fixes decoding failure with AMD driver.

Fixes #1223

Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/2574>