Merge branch 'add-support-for-mdb-offload-failure-notification'

Joseph Huang says:

====================
Add support for mdb offload failure notification

Currently the bridge does not provide real-time feedback to user space
on whether or not an attempt to offload an mdb entry was successful.

This patch set adds support to notify user space about failed offload
attempts, and is controlled by a new knob mdb_offload_fail_notification.

A break-down of the patches in the series:

Patch 1 adds offload failed flag to indicate that the offload attempt
has failed. The flag is reflected in netlink mdb entry flags.

Patch 2 adds the new bridge bool option mdb_offload_fail_notification.

Patch 3 notifies user space when the result is known, controlled by
mdb_offload_fail_notification setting.
====================

Link: https://patch.msgid.link/20250411150323.1117797-1-Joseph.Huang@garmin.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>