net: mscc: ocelot: fix eMAC TX RMON stats for bucket 256-511 and above

There is a typo in the driver due to which we report incorrect TX RMON
counters for the 256-511 octet bucket and all the other buckets larger
than that.

Bug found with the selftest at
https://patchwork.kernel.org/project/netdevbpf/patch/20231211223346.2497157-9-tobias@waldekranz.com/

Fixes: e32036e1

 ("net: mscc: ocelot: add support for all sorts of standardized counters present in DSA")
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Florian Fainelli <florian.fainelli@broadcom.com>
Link: https://lore.kernel.org/r/20231214000902.545625-1-vladimir.oltean@nxp.com


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