Add missing NULL checks to USB drivers.

Should fix #17276, #17846.

src/add-ons/kernel/drivers/audio/usb/Device.cpp

@@ -795,6 +795,8 @@ Device::_SetupEndpoints()
 
 	for (size_t i = 0; i < config->interface_count; i++) {
 		usb_interface_info* Interface = config->interface[i].active;
+		if (Interface == NULL || Interface->descr == NULL)
+			continue;
 		if (Interface->descr->interface_class != USB_AUDIO_INTERFACE_AUDIO_CLASS)
 			continue;
 

src/add-ons/kernel/drivers/input/usb_hid/Driver.cpp

@@ -105,6 +105,9 @@ usb_hid_device_added(usb_device device, void **cookie)
 	int32 parentCookie = atomic_add(&sParentCookie, 1);
 	for (size_t i = 0; i < config->interface_count; i++) {
 		const usb_interface_info *interface = config->interface[i].active;
+		if (interface == NULL || interface->descr == NULL)
+			continue;
+
 		uint8 interfaceClass = interface->descr->interface_class;
 		TRACE("interface %" B_PRIuSIZE ": class: %u; subclass: %u; protocol: "
 			"%u\n",	i, interfaceClass, interface->descr->interface_subclass,

src/libs/compat/freebsd_network/usb.cpp

@@ -89,7 +89,13 @@ get_next_usb_device(uint32* cookie, freebsd_usb_device* result)
 	result->endpoints_max = 0;
 	for (size_t i = 0; i < config->interface_count; i++) {
 		usb_interface_info* iface = config->interface[i].active;
+		if (iface == NULL)
+			continue;
+
 		for (size_t j = 0; j < iface->endpoint_count; j++) {
+			if (iface->endpoint[j].descr == NULL)
+				continue;
+
 			const int rep = result->endpoints_max++;
 			result->endpoints[rep].iface_index = i;