net: dsa: b53: Bound check ARL searches

ARL searches are done by reading two ARL entries at a time, do not cap
the search at 1024 which would only limit us to half of the possible ARL
capacity, but use b53_max_arl_entries() instead which does the right
multiplication between bins and indexes.

Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>