of/fdt: fix allocation size for device node path

The allocation size of device node path is off by one which drops the
'\0' terminator.

Signed-off-by: Ricky Liang <jcliang@chromium.org>
Signed-off-by: Rob Herring <robh@kernel.org>

drivers/of/fdt.c

@@ -191,7 +191,7 @@ static void * unflatten_dt_node(void *blob,
 	if (!pathp)
 		return mem;
 
-	allocl = l++;
+	allocl = ++l;
 
 	/* version 0x10 has a more compact unit name here instead of the full
 	 * path. we accumulate the full path size using "fpsize", we'll rebuild