cmd_mac: Move conditional compilation to Makefile

finish remaning CFG_ID_EEPROM in CONFIG_ID_EEPROM
start in commit ad8f8687b78c3e917b173f038926695383c55555

Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
diff --git a/include/configs/MPC8641HPCN.h b/include/configs/MPC8641HPCN.h
index 54a0461..a57c303 100644
--- a/include/configs/MPC8641HPCN.h
+++ b/include/configs/MPC8641HPCN.h
@@ -151,7 +151,7 @@
 
 #define CONFIG_ID_EEPROM
 #define CFG_I2C_EEPROM_NXID
-#define CFG_ID_EEPROM
+#define CONFIG_ID_EEPROM
 #define CFG_I2C_EEPROM_ADDR     0x57
 #define CFG_I2C_EEPROM_ADDR_LEN 1