cli: Avoid sending ANSI characters to a non-terminal

Detect if there is no terminal present (this only works on sandbox) and
skip sending ANSI characters when the CLI starts up. This avoids having
them in logs, for example.

Signed-off-by: Simon Glass <sjg@chromium.org>

common/cli.c

@@ -20,6 +20,7 @@
 #include <fdtdec.h>
 #include <hang.h>
 #include <malloc.h>
+#include <serial.h>
 #include <asm/global_data.h>
 #include <dm/ofnode.h>
 #include <linux/errno.h>
@@ -337,6 +338,6 @@ void cli_init(void)
 	hush_init_var();
 #endif
 
-	if (CONFIG_IS_ENABLED(VIDEO_ANSI))
+	if (CONFIG_IS_ENABLED(VIDEO_ANSI) && serial_is_tty())
 		printf(ANSI_CURSOR_SHOW "\n");
 }