nir/lower_tex: ignore texture_index if tex_instr has deref src
texture_index is meaningless when a tex_instr has deref src. Use var->data.binding instead. This fixes the incorrect lowering on radeonsi where the same lowering steps was applied to all tex_instr based on the needs of the first one (since texture_index is always 0). CC: mesa-stable Reviewed-by:Jesse Natalie <jenatali@microsoft.com> Acked-by:
Marek Olšák <marek.olsak@amd.com> Part-of: <mesa/mesa!9931> (cherry picked from commit bc438c91)