Skip all admin down ports for non-Mellanox device (#6433)

* remove asic type and speed check, skip all admin down ports on broadcom's device

What is the motivation for this PR?
There was no BUFFER_PROFILE_TABLE for admin down ports

How did you do it?
Skip all admin down ports for Broadcom device

How did you verify/test it?
Verify the original failure case

Signed-off-by: xuliping <xuliping@microsoft.com>

Author: lipxu

tests/qos/test_buffer.py

@@ -2481,15 +2481,8 @@ def _check_port_buffer_info_and_return(duthost, table, ids, port, expected_profi
         else:
             if is_mellanox_device(duthost):
                 buffer_items_to_check = buffer_items_to_check_dict["down"][key_name]
-            elif is_broadcom_device(duthost) and (asic_type in ['td2', 'td3'] or speed <= '10000'):
-                buffer_items_to_check = [(None, None, None)]
             else:
-                if key_name == KEY_2_LOSSLESS_QUEUE:
-                    buffer_items_to_check = [('BUFFER_PG_TABLE', '3-4', profile_wrapper.format(expected_profile))]
-                else:
-                    buffer_items_to_check.extend(
-                        [('BUFFER_PG_TABLE', '2-4', profile_wrapper.format(expected_profile)),
-                        ('BUFFER_PG_TABLE', '6', profile_wrapper.format(expected_profile))])
+                buffer_items_to_check = [(None, None, None)]
 
         for table, ids, expected_profile in buffer_items_to_check:
             logging.info("Checking buffer item {}:{}:{}".format(table, port, ids))