remote-sim host tools: Auto-discover the endpoint addresses

We now auto-discover the end-point addresses based on the interface
descriptor.  The user can also use the new "--interface" command line
argument to set a non-zero intrerface.  In combination, this should
enable support for the remote-sim functionality on the second UART
on OWHW.

host/simtrace2-discovery.h

@@ -0,0 +1,7 @@
+#pragma once
+
+#include <stdint.h>
+#include <libusb.h>
+
+int get_usb_ep_addrs(libusb_device_handle *devh, unsigned int if_num,
+		     uint8_t *out, uint8_t *in, uint8_t *irq);