net/mlx5e: Update and set Xon/Xoff upon port speed set

Xon/Xoff sizes are derived from calculations that include
the port speed.
These settings need to be updated and applied whenever the
port speed is changed.
The port speed is typically set after the physical link goes down
and is negotiated as part of the link-up process between the two
connected interfaces.
Xon/Xoff parameters being updated at the point where the new
negotiated speed is established.

Fixes: 0696d608 ("net/mlx5e: Receive buffer configuration")
Signed-off-by: Alexei Lazar <alazar@nvidia.com>
Reviewed-by: Tariq Toukan <tariqt@nvidia.com>
Signed-off-by: Mark Bloch <mbloch@nvidia.com>
Link: https://patch.msgid.link/20250825143435.598584-11-mbloch@nvidia.com


Signed-off-by: Jakub Kicinski <kuba@kernel.org>