cli_simple.c: fix possible overflow when copying the string

Bigger source buffer than dest buffer could overflow when copying
strings.  Source and destination buffer sizes are same now.

Signed-off-by: Imran Zaman <imran.zaman@intel.com>

common/cli_simple.c

@@ -258,7 +258,7 @@ int cli_simple_run_command(const char *cmd, int flag)
 
 void cli_simple_loop(void)
 {
-	static char lastcommand[CONFIG_SYS_CBSIZE] = { 0, };
+	static char lastcommand[CONFIG_SYS_CBSIZE + 1] = { 0, };
 
 	int len;
 	int flag;