brymen-bm86x: rename specific Brymen BM86x driver (libusb implementation)

The src/hardware/brymen-bm86x/ source code contains specific support for
the Brymen BM86x devices, and directly depends on the libusb library.
Rename the registered device (append the "-usb" suffix) before adding
BM86x support to the serial-dmm driver.

src/hardware/brymen-bm86x/api.c

@@ -200,7 +200,7 @@ static int dev_acquisition_stop(struct sr_dev_inst *sdi)
 }
 
 static struct sr_dev_driver brymen_bm86x_driver_info = {
-	.name = "brymen-bm86x",
+	.name = "brymen-bm86x-usb",
 	.longname = "Brymen BM86X",
 	.api_version = 1,
 	.init = std_init,