CHANGELOG:Add entry for downstream endpoint bridge polling

Signed-off-by: Faizan Ali <faizana@nvidia.com>

Author: faizana-nvidia

CHANGELOG.md

@@ -42,6 +42,10 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
    message types. Those types are reported in `mctpd`'s responses to
    Get Message Type Support and Get MCTP Version support commands.
 
+9. `mctpd` now implements bridge endpoint polling after successful dynamic pool
+   space allocation. Once endpoint is establised as accessible i.e if it responds
+   to send poll command, polling on that endpoint would stop.
+
 ## [2.2] - 2025-07-28
 
 ### Fixed