net: dsa: microchip: Refactor comment for ksz_switch_macaddr_get() function

Update the comment to follow kernel-doc format.

Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
Reviewed-by: Florian Fainelli <florian.fainelli@broadcom.com>
Reviewed-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Link: https://lore.kernel.org/r/20231026051051.2316937-3-o.rempel@pengutronix.de


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