m53menlo: fix addmtd cmd in default environment

The original definition added the string mtdparts= to the Linux Kernel
args twice: mtdparts=mtdparts=. Fix that.

Signed-off-by: Olaf Mandel <o.mandel@menlosystems.com>
Reviewed-by: Marek Vasut <marex@denx.de>
diff --git a/include/configs/m53menlo.h b/include/configs/m53menlo.h
index 257a4cb..51456fb 100644
--- a/include/configs/m53menlo.h
+++ b/include/configs/m53menlo.h
@@ -215,7 +215,7 @@
 		"setenv bootargs ${bootargs} "				\
 		"ip=${ipaddr}:${serverip}:${gatewayip}:${netmask}"	\
 		":${hostname}:${netdev}:off\0"				\
-	"addmtd=setenv bootargs ${bootargs} mtdparts=${mtdparts}\0"	\
+	"addmtd=setenv bootargs ${bootargs} ${mtdparts}\0"		\
 	"addmisc="							\
 		"setenv bootargs ${bootargs} ${miscargs}\0"		\
 	"addargs=run addcons addmisc addmtd\0"				\