Add boot delay and handshake retry logic

- Add 100ms delay before device initialization to allow USB power stabilization
- Implement retry logic (3 attempts) for initial handshake with 50ms between retries
- Warn on each failed handshake attempt

This addresses enumeration failures during system boot where the US-200
needs additional time to become ready after USB bus power-up.

us144mkii.c

@@ -253,9 +253,18 @@ static int tascam_probe(struct usb_interface *intf, const struct usb_device_id *
 		goto free_card;
 	}
 
-	usb_control_msg(dev, usb_rcvctrlpipe(dev, 0), VENDOR_REQ_MODE_CONTROL,
+	msleep(100);
+
+	for (int retry = 0; retry < 3; retry++) {
+		int handshake_result = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0), VENDOR_REQ_MODE_CONTROL,
 					RT_D2H_VENDOR_DEV, MODE_VAL_HANDSHAKE_READ, 0x0000,
 				 tascam->scratch_buf, 1, USB_CTRL_TIMEOUT_MS);
+		if (handshake_result >= 0)
+			break;
+
+		dev_warn(&dev->dev, "Handshake failed (attempt %d/3), retrying...\n", retry + 1);
+		msleep(50);
+	}
 
 	usb_set_interface(dev, 0, 1);
 	usb_set_interface(dev, 1, 1);