Fix np bfloat16 misinterpreted as complex (#3146)

Co-authored-by: Cheng <git@zcbenz.com>

python/src/array.cpp

@@ -296,7 +296,7 @@ void init_array(nb::module_& m) {
       nb::is_weak_referenceable())
       .def(
           "__init__",
-          [](mx::array* aptr, ArrayInitType v, std::optional<mx::Dtype> t) {
+          [](mx::array* aptr, nb::object v, std::optional<mx::Dtype> t) {
             new (aptr) mx::array(create_array(v, t));
           },
           "val"_a,
@@ -492,7 +492,7 @@ void init_array(nb::module_& m) {
                      reinterpret_cast<const size_t*>(nd.shape_ptr()),
                      owner,
                      nullptr,
-                     nb::bfloat16),
+                     nb::dtype<mx::bfloat16_t>()),
                   mx::bfloat16));
             } else {
               new (&arr) mx::array(nd_array_to_mlx(nd, std::nullopt));