v3d: no specific separate_segments flag for V3D 7.1

v3d: no specific separate_segments flag for V3D 7.1

On V3D 7.1 there is not a flag on the Shader State Record to specify
if we are using shared or separate segments. This is done by setting
the vpm input size to 0 (so we need to ensure that the output would be
the max needed for input/output).

We were already doing the latter on the prog_data_vs, so we just need
to use those values, instead of assigning default values.

Reviewed-by: Iago Toral Quiroga <itoral@igalia.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/25450>