bootstd: usb: Avoid initing USB twice

This causes crashes on some boards, e.g. rockpro64. In any case, we
should not do it.

Check the usb_started flag to avoid this.

Signed-off-by: Simon Glass <sjg@chromium.org>
Tested-by: Jonas Karlman <jonas@kwiboo.se>
Tested-by: Tom Rini <trini@konsulko.com>
diff --git a/test/boot/bootdev.c b/test/boot/bootdev.c
index 606bf4f..6b29213 100644
--- a/test/boot/bootdev.c
+++ b/test/boot/bootdev.c
@@ -306,6 +306,7 @@
 {
 	struct bootstd_priv *std;
 
+	usb_started = false;
 	test_set_skip_delays(true);
 
 	/* get access to the used hunters */
@@ -346,6 +347,7 @@
 	struct bootstd_priv *std;
 
 	test_set_skip_delays(true);
+	usb_started = false;
 
 	/* get access to the used hunters */
 	ut_assertok(bootstd_get_priv(&std));
@@ -474,6 +476,7 @@
 /* Check hunting for bootdev of a particular priority */
 static int bootdev_test_hunt_prio(struct unit_test_state *uts)
 {
+	usb_started = false;
 	test_set_skip_delays(true);
 
 	console_record_reset_enable();
@@ -502,6 +505,8 @@
 	struct bootstd_priv *std;
 	int mflags;
 
+	usb_started = false;
+
 	/* get access to the used hunters */
 	ut_assertok(bootstd_get_priv(&std));