Fix "cpu" to "llvm-cpu" in one last Colab notebook. (#10104)

diff --git a/samples/dynamic_shapes/dynamic_shapes.ipynb b/samples/dynamic_shapes/dynamic_shapes.ipynb
index 392c816..b2d04e4 100644
--- a/samples/dynamic_shapes/dynamic_shapes.ipynb
+++ b/samples/dynamic_shapes/dynamic_shapes.ipynb
@@ -275,10 +275,10 @@
         "\n",
         "from iree.compiler import compile_str\n",
         "\n",
-        "# Note: we'll use the cpu (LLVM) backend since it has the best support\n",
+        "# Note: we'll use the LLVM CPU backend since it has the best support\n",
         "# for dynamic shapes among our compiler targets.\n",
         "\n",
-        "flatbuffer_blob = compile_str(compiler_module, target_backends=[\"cpu\"], input_type=\"mhlo\")\n",
+        "flatbuffer_blob = compile_str(compiler_module, target_backends=[\"llvm-cpu\"], input_type=\"mhlo\")\n",
         "\n",
         "# Save the compiled program to disk.\n",
         "flatbuffer_path = os.path.join(ARTIFACTS_DIR, \"dynamic_shapes_cpu.vmfb\")\n",