[QoS] Support dynamic headroom calculation for Barefoot platforms (sonic-net#2306)

Signed-off-by: Mariusz Stachura <[email protected]>

What I did
Adding the dynamic headroom calculation support for Barefoot platforms.

Why I did it
Enabling dynamic mode for barefoot case.

How I verified it
The community tests are adjusted and pass.

Author: MariuszStachura

config/main.py

@@ -2645,7 +2645,7 @@ def reload(ctx, no_dynamic_buffer, dry_run, json_data, ports):
         namespace_list = multi_asic.get_namespaces_from_linux()
 
     buffer_model_updated = False
-    vendors_supporting_dynamic_buffer = ["mellanox"]
+    vendors_supporting_dynamic_buffer = ["mellanox", "barefoot"]
 
     for ns in namespace_list:
         if ns is DEFAULT_NAMESPACE: