net/mlx5e: Add helper function to update IPSec default destination

The default destination of IPSec steering rules for MPV mode will be
updated when the master device is brought up or down. Move the common
code into the helper function. It’s convenient to update destinations
in later patches.

Signed-off-by: Jianbo Liu <jianbol@nvidia.com>
Reviewed-by: Leon Romanovsky <leonro@nvidia.com>
Reviewed-by: Patrisious Haddad <phaddad@nvidia.com>
Signed-off-by: Tariq Toukan <tariqt@nvidia.com>
Link: https://patch.msgid.link/20250220213959.504304-2-tariqt@nvidia.com


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