net: dsa: b53: move reading ARL entries into their own function

net: dsa: b53: move reading ARL entries into their own function

Instead of duplicating the whole code iterating over all bins for
BCM5325, factor out reading and parsing the entry into its own
functions, and name it the modern one after the first chip with that ARL
format, (BCM53)95.

Signed-off-by: Jonas Gorski <jonas.gorski@gmail.com>
Reviewed-by: Florian Fainelli <florian.fainelli@broadcom.com>
Link: https://patch.msgid.link/20251107080749.26936-3-jonas.gorski@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>