usb: Fix printf format in debug string

The parameter is a uint16_t, therefore the format specifier should be
%hu and not %hhu.

Signed-off-by: Paul Cercueil <[email protected]>

Author: pcercuei

usb.c

@@ -928,7 +928,7 @@ static struct iio_context * usb_create_context(unsigned int bus,
 
 	pdata->nb_ep_couples = iface->bNumEndpoints / 2;
 
-	IIO_DEBUG("Found %hhu usable i/o endpoint couples\n", pdata->nb_ep_couples);
+	IIO_DEBUG("Found %hu usable i/o endpoint couples\n", pdata->nb_ep_couples);
 
 	pdata->io_endpoints = calloc(pdata->nb_ep_couples,
 			sizeof(*pdata->io_endpoints));