intel/compiler: fix uninit non-static variable. (v2)

Pointed out by coverity.

v2: init nir_locals also.

Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>

src/intel/compiler/brw_vec4_visitor.cpp

@@ -1889,6 +1889,9 @@ vec4_visitor::vec4_visitor(const struct brw_compiler *compiler,
    this->max_grf = devinfo->gen >= 7 ? GEN7_MRF_HACK_START : BRW_MAX_GRF;
 
    this->uniforms = 0;
+
+   this->nir_locals = NULL;
+   this->nir_ssa_values = NULL;
 }