Fix uninit variable warnings.

driver-avalon.c

@@ -652,7 +652,8 @@ static int bitburner_get_core_voltage(struct cgpu_info *avalon)
 
 static bool avalon_detect_one(libusb_device *dev, struct usb_find_devices *found)
 {
-	int baud, miner_count, asic_count, timeout, frequency = 0;
+	int baud, uninitialised_var(miner_count), uninitialised_var(asic_count),
+	    uninitialised_var(timeout), frequency = 0;
 	int this_option_offset = ++option_offset;
 	struct avalon_info *info;
 	struct cgpu_info *avalon;

usbutils.c

@@ -1801,7 +1801,7 @@ out_unlock:
 bool usb_init(struct cgpu_info *cgpu, struct libusb_device *dev, struct usb_find_devices *found_match)
 {
 	struct usb_find_devices *found_use = NULL;
-	int ret;
+	int uninitialised_var(ret);
 	int i;
 
 	for (i = 0; find_dev[i].drv != DRV_LAST; i++) {