drivers/hwmon: add module.h to ultra45_env.c

This file needs the full module.h header and up to now was just
implicitly capitalizing on it being present already.

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
diff --git a/drivers/hwmon/ultra45_env.c b/drivers/hwmon/ultra45_env.c
index 27a6271..3cd07bf 100644
--- a/drivers/hwmon/ultra45_env.c
+++ b/drivers/hwmon/ultra45_env.c
@@ -6,6 +6,7 @@
 #include <linux/kernel.h>
 #include <linux/types.h>
 #include <linux/slab.h>
+#include <linux/module.h>
 #include <linux/of_device.h>
 #include <linux/io.h>
 #include <linux/hwmon.h>