nir: Add 64-bit integer constant support

v2: Rebase on 19a541f (nir: Get rid of nir_constant_data)

Signed-off-by: Ian Romanick <ian.d.romanick@intel.com>
Reviewed-by: Connor Abbott <cwabbott0@gmail.com> [v1]

src/compiler/nir/nir.c

@@ -846,6 +846,8 @@ nir_deref_get_const_initializer_load(nir_shader *shader, nir_deref_var *deref)
    case GLSL_TYPE_INT:
    case GLSL_TYPE_UINT:
    case GLSL_TYPE_DOUBLE:
+   case GLSL_TYPE_UINT64:
+   case GLSL_TYPE_INT64:
    case GLSL_TYPE_BOOL:
       load->value = constant->values[matrix_col];
       break;