qlcnic: Implement ndo_get_phys_port_id for 82xx adapter

Each function driver instance uses the MAC address of the
lowest function belonging to that physical port as a unique
port identifier. This port identifier is read and cached in
driver during probe and provided to user space through
ndo_get_phys_port_id()

Signed-off-by: Shahed Shaikh <shahed.shaikh@qlogic.com>
Signed-off-by: Himanshu Madhani <himanshu.madhani@qlogic.com>
Signed-off-by: David S. Miller <davem@davemloft.net>