Introduce a new test, `ipv4_devconf_notify`, to verify that the kernel sends the appropriate netlink notifications when IPv4 devconf parameters are modified. The test depends on the newly introduced iproute2 command: `ip link set dev <ifname> inet` Signed-off-by: Fernando Fernandez Mancera <fmancera@suse.de> Link: https://patch.msgid.link/20260609204520.4670-3-fmancera@suse.de Signed-off-by: Jakub Kicinski <kuba@kernel.org>