net: dsa: realtek: remove direct calls to realtek-smi

Remove the only two direct calls from subdrivers to realtek-smi.
Now they are called from realtek_priv. Subdrivers can now be
linked independently from realtek-smi.

Signed-off-by: Luiz Angelo Daros de Luca <luizluca@gmail.com>
Reviewed-by: Alvin Šipraga <alsi@bang-olufsen.dk>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>