Initial driver registration mechanism

Also added the basis of the upekts driver, which is the first I'll
implement.

libfprint/core.c

@@ -19,7 +19,31 @@
 
 #include <config.h>
 
+#include <glib.h>
+
+#include "fp_internal.h"
+
+static GList *registered_drivers = NULL;
+
+static void register_driver(const struct fp_driver *drv)
+{
+	registered_drivers = g_list_prepend(registered_drivers, (gpointer) drv);
+}
+
+static const struct fp_driver * const drivers[] = {
+	&upekts_driver,
+};
+
+static void register_drivers(void)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(drivers); i++)
+		register_driver(drivers[i]);
+}
+
 API_EXPORTED int fp_init(void)
 {
+	register_drivers();
 	return 0;
 }