lib: Fix mess with driver IDs

ID is just a some magic number to make fingerprint from one scanner model
incompatible with another scanner model. Get rid of "magic", declare enum
and use it.

https://bugs.freedesktop.org/show_bug.cgi?id=56956

libfprint/drivers/aes4000.c

@@ -27,6 +27,8 @@
 #include <aeslib.h>
 #include <fp_internal.h>
 
+#include "driver_ids.h"
+
 #define CTRL_TIMEOUT	1000
 #define EP_IN			(1 | LIBUSB_ENDPOINT_IN)
 #define EP_OUT			(2 | LIBUSB_ENDPOINT_OUT)
@@ -249,7 +251,7 @@ static const struct usb_id id_table[] = {
 
 struct fp_img_driver aes4000_driver = {
 	.driver = {
-		.id = 3,
+		.id = AES4000_ID,
 		.name = FP_COMPONENT,
 		.full_name = "AuthenTec AES4000",
 		.id_table = id_table,