net: dsa: microchip: ksz9477: reduce polling interval for statistics

30 seconds is too long interval especially if it used with ip -s l.
Reduce polling interval to 5 sec.

Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
Link: https://lore.kernel.org/r/20220221084129.3660124-1-o.rempel@pengutronix.de


Signed-off-by: Jakub Kicinski <kuba@kernel.org>