After adding cpsw_set_ringparam ethtool op, better to carry out
common parts of similar ops splitting descriptors in runtime. It
allows to reuse these parts and shows what the ops actually do.
Signed-off-by: NIvan Khoronzhuk <ivan.khoronzhuk@linaro.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>