net: dsa: make function ksz_rcv static

function ksz_rcv can be made static as it does not need to be
in global scope. Reformat arguments to make it checkpatch warning
free too.

Cleans up sparse warning: "symbol 'ksz_rcv' was not declared. Should
it be static?"

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Reviewed-by: Woojung Huh <Woojung.Huh@microchip.com>
Signed-off-by: David S. Miller <davem@davemloft.net>