Fix typo in cpu/mpc85xx/cpu.c

CONFIG_MPC85xx_FEC -> CONFIG_MPC85XX_FEC

Signed-off-by: Ben Warren <biggerbadderben@gmail.com>
diff --git a/cpu/mpc85xx/cpu.c b/cpu/mpc85xx/cpu.c
index c780687..b90871d 100644
--- a/cpu/mpc85xx/cpu.c
+++ b/cpu/mpc85xx/cpu.c
@@ -383,7 +383,7 @@
  */
 int cpu_eth_init(bd_t *bis)
 {
-#if defined(CONFIG_TSEC_ENET) || defined(CONFIG_MPC85xx_FEC)
+#if defined(CONFIG_TSEC_ENET) || defined(CONFIG_MPC85XX_FEC)
 	tsec_standard_init(bis);
 #endif