configs: Update Lamobo_R1 with B53 switch options

Enable CONFIG_B53_SWITCH, define the CPU/management port number (8) and
enable all 5 ports of the switch to be usable.

Reviewed-by: Stefan Roese <sr@denx.de>
Acked-by: Joe Hershberger <joe.hershberger@ni.com>
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>