netconsole: add STATE_DEACTIVATED to track targets disabled by low level

netconsole: add STATE_DEACTIVATED to track targets disabled by low level

When the low level interface brings a netconsole target down, record this
using a new STATE_DEACTIVATED state. This allows netconsole to distinguish
between targets explicitly disabled by users and those deactivated due to
interface state changes.

It also enables automatic recovery and re-enabling of targets if the
underlying low-level interfaces come back online.

From a code perspective, anything that is not STATE_ENABLED is disabled.

Devices (de)enslaving are marked STATE_DISABLED to prevent automatically
resuming as enslaved interfaces cannot have netconsole enabled.

Signed-off-by: Breno Leitao <leitao@debian.org>
Signed-off-by: Andre Carvalho <asantostc@gmail.com>
Tested-by: Breno Leitao <leitao@debian.org>
Link: https://patch.msgid.link/20260118-netcons-retrigger-v11-3-4de36aebcf48@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>