Fix quoting problem (preboot setting) in many board config files.

Signed-off-by: Wolfgang Denk <wd@denx.de>
diff --git a/include/configs/idmr.h b/include/configs/idmr.h
index 3821ebc..a15f69a 100644
--- a/include/configs/idmr.h
+++ b/include/configs/idmr.h
@@ -57,7 +57,7 @@
 #define CONFIG_NETMASK		255.255.0.0
 #define CONFIG_HOSTNAME		idmr
 #define CONFIG_BOOTFILE		/tftpboot/idmr/uImage
-#define CONFIG_PREBOOT		"echo;echo Type \"run flash_nfs\" to mount root " \
+#define CONFIG_PREBOOT		"echo;echo Type \\\"run flash_nfs\\\" to mount root " \
 				"filesystem over NFS; echo"
 
 #define CONFIG_MCFTMR