net/mlx5e: Defer channels closure to reduce interface down time

net/mlx5e: Defer channels closure to reduce interface down time

Cap bit tis_tir_td_order=1 indicates that an old firmware requirement /
limitation no longer exists. When unset, the latency of several firmware
commands significantly increases with the presence of high number of
co-existing channels (both old and new sets). Hence, we used to close
unneeded old channels before invoking those firmware commands.

Today, on capable devices, this is no longer the case. Minimize the
interface down time by deferring the old channels closure, after the
activation of the new ones.

Perf numbers:
Measured the number of dropped packets in a simple ping flood test,
during a configuration change operation, that switches the number of
channels from 247 to 248.

Before: 71 packets lost
After:  15 packets lost, ~80% saving.

Signed-off-by: Tariq Toukan <tariqt@nvidia.com>
Reviewed-by: Carolina Jubran <cjubran@nvidia.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/1761831159-1013140-8-git-send-email-tariqt@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>