netifd: add support for the new ar8xxx MIB counters settings
Commit "generic: ar8216: add mib_poll_interval switch attribute" has added
mib_poll_interval global config option and commit "generic: ar8216: group
MIB counters and use two basic ones only by default" has added mib_type
config option.
Signed-off-by: Petr Štetiar <[email protected]>