tgsi: catch sampler out of range early
Since we only support PIPE_MAX_SAMPLERS we should already bail out in tgsi_scan instead of relying on convert_shader to catch this issue.
This improves a6716eee (tgsi: Add sanity checks to avoid out-of-bound access)
Closes: https://gitlab.freedesktop.org/virgl/virglrenderer/-/issues/343
Edited by Gert Wollny