TCL scripts: fix ocd_mem2array/mem2array

In previous patch, I have introduced again the symbol
"ocd_mem2array", now replaced by "mem2array".
Fix the error.

Signed-off-by: Antonio Borneo <borneo.antonio@gmail.com>

tcl/mem_helper.tcl

@@ -3,7 +3,7 @@
 # mrw: "memory read word", returns value of $reg
 proc mrw {reg} {
 	set value ""
-	ocd_mem2array value 32 $reg 1
+	mem2array value 32 $reg 1
 	return $value(0)
 }