net: dsa: mv88e6xxx: add mv88e6xxx_num_ports helper

Add an mv88e6xxx_num_ports helper instead of digging in the chip info
structure.

Signed-off-by: Vivien Didelot <vivien.didelot@savoirfairelinux.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
3 files changed