net: Move initialization of Au1x00 SoC ethernet MAC to cpu_eth_init

This patch will move au1x00_eth_initialize from net/eth.c to cpu_eth_init
as a part of ongoing eth_initialize cleanup work.  The function ret value
is also fixed as it should be negative on fail.

Signed-off-by: Shinya Kuribayashi <skuribay@ruby.dti.ne.jp>
Signed-off-by: Ben Warren <biggerbadderben@gmail.com>
diff --git a/include/netdev.h b/include/netdev.h
index 3739980..31115e2 100644
--- a/include/netdev.h
+++ b/include/netdev.h
@@ -41,6 +41,7 @@
 int cpu_eth_init(bd_t *bis);
 
 /* Driver initialization prototypes */
+int au1x00_enet_initialize(bd_t*);
 int bfin_EMAC_initialize(bd_t *bis);
 int dc21x4x_initialize(bd_t *bis);
 int e1000_initialize(bd_t *bis);