doc: efm32: rmu: include in doxygen generation

Include a stub .c file for shared code generation

lib/efm32/common/rmu_common.c

@@ -0,0 +1,15 @@
+/** @addtogroup rmu_file RMU peripheral API
+ * @ingroup peripheral_apis
+ * @brief Reset Management Unit 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/rmu.h>
+
+/**@{*/
+
+/**@}*/
+

lib/efm32/ezr32wg/Makefile

@@ -49,6 +49,7 @@ OBJS += i2c_common.o
 OBJS += letimer_common.o
 OBJS += msc_common.o
 OBJS += prs_common.o
+OBJS += rmu_common.o
 OBJS += timer_common.o
 
 OBJS += usb.o usb_control.o usb_standard.o usb_msc.o

lib/efm32/lg/Makefile

@@ -49,6 +49,7 @@ OBJS += i2c_common.o
 OBJS += letimer_common.o
 OBJS += msc_common.o
 OBJS += prs_common.o
+OBJS += rmu_common.o
 OBJS += timer_common.o
 
 OBJS += usb.o usb_control.o usb_standard.o usb_msc.o

lib/efm32/wg/Makefile

@@ -49,6 +49,7 @@ OBJS += i2c_common.o
 OBJS += letimer_common.o
 OBJS += msc_common.o
 OBJS += prs_common.o
+OBJS += rmu_common.o
 OBJS += timer_common.o
 
 OBJS += usb.o usb_control.o usb_standard.o usb_msc.o