Fix implicit includes and follow c++ style cast

Change-Id: Icb2c9aa22b756e65a7969c1deecab65289f328ec
Signed-off-by: Brandon Kim <brandonkim@google.com>
diff --git a/nvmes.cpp b/nvmes.cpp
index 972d406..b936f8a 100644
--- a/nvmes.cpp
+++ b/nvmes.cpp
@@ -1,5 +1,9 @@
 #include "nvmes.hpp"
 
+#include <xyz/openbmc_project/Sensor/Threshold/Critical/server.hpp>
+#include <xyz/openbmc_project/Sensor/Threshold/Warning/server.hpp>
+#include <xyz/openbmc_project/Sensor/Value/server.hpp>
+
 namespace phosphor
 {
 namespace nvme