Update docs to remove mention of older models (#2557)

Author: tqchen

docs/get_started/quick_start.rst

@@ -133,7 +133,7 @@ It is recommended to have at least 6GB free VRAM to run it.
 
     |
 
-    **Requirement**. Llama3-8B model needs an iOS device with a minimum of 6GB RAM, whereas the RedPajama-3B model runs with at least 4GB RAM.
+    **Note**. The larger model might take more VRAM, try start with smaller models first.
 
     **Tutorial and source code**. The source code of the iOS app is fully `open source <https://github.com/mlc-ai/mlc-llm/tree/main/ios>`__,
     and a :ref:`tutorial <deploy-ios>` is included in documentation.
@@ -154,7 +154,7 @@ It is recommended to have at least 6GB free VRAM to run it.
 
     |
 
-    **Requirement**. Llama3-8B model needs a device with a minimum of 6GB RAM, whereas the RedPajama-3B model runs with at least 4GB RAM.
+    **Note**. The larger model might take more VRAM, try start with smaller models first.
     The demo is tested on
 
     - Samsung S23 with Snapdragon 8 Gen 2 chip