doc: efm32: wdog: include stub file

Tags were added, but without the stub file, common headers aren't picked
up by the auto source list generation

lib/efm32/common/wdog_common.c

@@ -0,0 +1,15 @@
+/** @addtogroup wdog_file WDOG peripheral API
+ * @ingroup peripheral_apis
+ * @brief Watchdog Module helper functions.
+ *
+ * <b>NO</b> helper functions exist. Only header definitions are available.
+ * Delete these lines if/when you add actual helper APIs.
+ * @copyright See @ref lgpl_license
+ */
+
+#include <libopencm3/efm32/wdog.h>
+
+/**@{*/
+
+/**@}*/
+

lib/efm32/ezr32wg/Makefile

@@ -51,6 +51,7 @@ OBJS += msc_common.o
 OBJS += prs_common.o
 OBJS += rmu_common.o
 OBJS += timer_common.o
+OBJS += wdog_common.o
 
 OBJS += usb.o usb_control.o usb_standard.o usb_msc.o
 OBJS += usb_efm32.o

lib/efm32/lg/Makefile

@@ -51,6 +51,7 @@ OBJS += msc_common.o
 OBJS += prs_common.o
 OBJS += rmu_common.o
 OBJS += timer_common.o
+OBJS += wdog_common.o
 
 OBJS += usb.o usb_control.o usb_standard.o usb_msc.o
 OBJS += usb_efm32.o

lib/efm32/wg/Makefile

@@ -51,6 +51,7 @@ OBJS += msc_common.o
 OBJS += prs_common.o
 OBJS += rmu_common.o
 OBJS += timer_common.o
+OBJS += wdog_common.o
 
 OBJS += usb.o usb_control.o usb_standard.o usb_msc.o
 OBJS += usb_efm32.o