net: dsa: realtek: rtl8365mb: correct the max number of ports

The maximum number of ports is actually 11, according to two
observations:

1. The highest port ID used in the vendor driver is 10. Since port IDs
   are indexed from 0, and since DSA follows the same numbering system,
   this means up to 11 ports are to be presumed.

2. The registers with port mask fields always amount to a maximum port
   mask of 0x7FF, corresponding to a maximum 11 ports.

In view of this, I also deleted the comment.

Signed-off-by: Alvin Šipraga <alsi@bang-olufsen.dk>
Reviewed-by: Luiz Angelo Daros de Luca <luizluca@gmail.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>