nir: initialize value in copy_prop_vars_block
Fixes following valgrind warning:
==27561== Conditional jump or move depends on uninitialised value(s) ==27561== at 0x667856B: value_set_ssa_components (nir_opt_copy_prop_vars.c:78) ==27561== by 0x667A1C4: copy_prop_vars_block (nir_opt_copy_prop_vars.c:797)
Fixes: 62332d13 "nir: Add a local variable-based copy propagation pass" Signed-off-by: Tapani Pälli tapani.palli@intel.com