ARM: sheevaplug: unbreak default environment

Commit 1e3d640316 (ARM: sheevaplug: redefine MTDPARTS) changed the mtdparts
part of the default environment, but dropped the trailing zero termination -
So the definition of x_bootcmd_kernel becomes part of the x_bootargs
variable.

Fix it by reintroducing the zero termination.

Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

include/configs/sheevaplug.h

@@ -65,7 +65,7 @@
 #define CONFIG_MTDPARTS		\
 	"mtdparts=orion_nand:512K(uboot),"				\
 	"512K(env),1M(script),6M(kernel),"				\
-	"12M(ramdisk),4M(spare),-(rootfs)"
+	"12M(ramdisk),4M(spare),-(rootfs)\0"
 
 #define CONFIG_EXTRA_ENV_SETTINGS	"x_bootargs=console"	\
 	"=ttyS0,115200 mtdparts="CONFIG_MTDPARTS	\