[MIPS] Pb1200: do register SMC 91C111

Pb1200 does have SMC 91C111 Ethernet chip on board but the platform code
did not register it, so one couldn't mount NFS...

Signed-off-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>