rtc: Add module.h to implicit users in drivers/rtc

The module.h was implicitly everywhere, but when we clean
that up, the implicit users will compile fail; fix them up
in advance.

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>

drivers/rtc/interface.c

@@ -13,6 +13,7 @@
 
 #include <linux/rtc.h>
 #include <linux/sched.h>
+#include <linux/module.h>
 #include <linux/log2.h>
 #include <linux/workqueue.h>