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/lib_ppc/board.c b/lib_ppc/board.c
index c8f075f..4d02eb2 100644
--- a/lib_ppc/board.c
+++ b/lib_ppc/board.c
@@ -873,7 +873,7 @@
 	sc3_read_eeprom();
 #endif
 
-#if defined (CFG_ID_EEPROM) || defined (CFG_I2C_MAC_OFFSET)
+#if defined (CONFIG_ID_EEPROM) || defined (CFG_I2C_MAC_OFFSET)
 	mac_read_from_eeprom();
 #endif