net/mlx5: devcom, expose locked variant of send_event

net/mlx5: devcom, expose locked variant of send_event

Factor mlx5_devcom_send_event() into two functions:
- mlx5_devcom_locked_send_event(): performs the dispatch (and
  rollback) with comp->sem already held by the caller.
- mlx5_devcom_send_event(): unchanged wrapper that takes comp->sem,
  calls the locked variant, and releases it.

This lets callers bracket multiple event broadcasts under a single
held write lock, eliminating the gap between consecutive dispatches
where peer state could change.

Will be used by a downstream patch.

Signed-off-by: Shay Drory <shayd@nvidia.com>
Reviewed-by: Mark Bloch <mbloch@nvidia.com>
Signed-off-by: Tariq Toukan <tariqt@nvidia.com>
Link: https://patch.msgid.link/20260612113904.537595-3-tariqt@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>