lima/ppir: Add undef handling
Add a ppir dummy node for nir_ssa_undef_instr, create a reg for it and mark it as undefined, so that regalloc can set it non-interfering to avoid register pressure.
Edited by Andreas Baierl
Add a ppir dummy node for nir_ssa_undef_instr, create a reg for it and mark it as undefined, so that regalloc can set it non-interfering to avoid register pressure.