exo2: implement through package2 decryption

libraries/libexosphere/include/exosphere.hpp

@@ -25,6 +25,7 @@
 #include <exosphere/gic.hpp>
 #include <exosphere/wdt.hpp>
 #include <exosphere/pkg1.hpp>
+#include <exosphere/pkg2.hpp>
 #include <exosphere/tsec.hpp>
 #include <exosphere/se.hpp>
 #include <exosphere/flow.hpp>