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>
diff --git a/drivers/rtc/rtc-ds1742.c b/drivers/rtc/rtc-ds1742.c
index d84a448d..e3e0f92 100644
--- a/drivers/rtc/rtc-ds1742.c
+++ b/drivers/rtc/rtc-ds1742.c
@@ -21,6 +21,7 @@
 #include <linux/rtc.h>
 #include <linux/platform_device.h>
 #include <linux/io.h>
+#include <linux/module.h>
 
 #define DRV_VERSION "0.4"