powerpc: mpc5xxx: remove redundant CONFIG_MPC5xxx definition

We do not have to define CONFIG_MPC5xxx in board config headers
(and start.S) because it is defined in arch/powerpc/cpu/mpc5xxx/config.mk.

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
diff --git a/include/configs/digsy_mtc.h b/include/configs/digsy_mtc.h
index bc5853e..2a8cb39 100644
--- a/include/configs/digsy_mtc.h
+++ b/include/configs/digsy_mtc.h
@@ -20,8 +20,7 @@
  * High Level Configuration Options
  */
 
-#define CONFIG_MPC5xxx		1	/* This is an MPC5xxx CPU */
-#define CONFIG_MPC5200		1	/* (more precisely an MPC5200 CPU) */
+#define CONFIG_MPC5200		1	/* This is an MPC5200 CPU */
 #define CONFIG_DIGSY_MTC	1	/* ... on InterControl digsyMTC board */
 
 /*