Moved initialization of plb2800 Ethernet driver to board_eth_init

Affected boards:
	purple

Removed initialization of controller from net/eth.c

Signed-off-by: Ben Warren <biggerbadderben@gmail.com>

include/netdev.h

@@ -54,6 +54,7 @@ int mpc5xxx_fec_initialize(bd_t *bis);
 int natsemi_initialize(bd_t *bis);
 int ns8382x_initialize(bd_t *bis);
 int pcnet_initialize(bd_t *bis);
+int plb2800_eth_initialize(bd_t *bis);
 int rtl8139_initialize(bd_t *bis);
 int rtl8169_initialize(bd_t *bis);
 int skge_initialize(bd_t *bis);