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

Signed-off-by: Wolfgang Denk <wd@denx.de>
diff --git a/include/configs/TQM823M.h b/include/configs/TQM823M.h
index a0c01b6..40dc26b 100644
--- a/include/configs/TQM823M.h
+++ b/include/configs/TQM823M.h
@@ -51,7 +51,7 @@
 
 #define CONFIG_BOARD_TYPES	1	/* support board types		*/
 
-#define CONFIG_PREBOOT	"echo;echo Type \"run flash_nfs\" to mount root filesystem over NFS;echo"
+#define CONFIG_PREBOOT	"echo;echo Type \\\"run flash_nfs\\\" to mount root filesystem over NFS;echo"
 
 #undef	CONFIG_BOOTARGS