This commit deprecates these legacy netmask get/set routines
net_if_ipv4_set_netmask()
net_if_ipv4_set_netmask_by_index()
net_if_ipv4_get_netmask()
as they do not work well if there are multiple IPv4 address
assigned to the network interface.
User should use these functions instead
net_if_ipv4_set_netmask_by_addr()
net_if_ipv4_set_netmask_by_addr_by_index()
net_if_ipv4_get_netmask_by_addr()
as they make sure the netmask it bound to correct IPv4 address.
Signed-off-by: Jukka Rissanen <jukka.rissanen@nordicsemi.no>
58b2a3dfd4