cpu: atmega_common: adapt to periph/pm

cpu/atmega_common/Makefile.include

@@ -12,6 +12,7 @@ export LINKFLAGS += -Wl,--gc-sections -static -lgcc
 
 # export the peripheral drivers to be linked into the final binary
 export USEMODULE += periph
+export USEMODULE += periph_common
 
 # the atmel port uses uart_stdio
 export USEMODULE += uart_stdio

cpu/atmega_common/periph/pm.c

@@ -12,7 +12,7 @@
  * @{
  *
  * @file
- * @brief       Implementation of the kernels reboot interface
+ * @brief       Implementation of common AVR periph/pm functions
  *
  * @author      Hinnerk van Bruinehsen <h.v.bruinehsen@fu-berlin.de>
  * @author      Kaspar Schleiser <kaspar@schleiser.de>
@@ -22,9 +22,10 @@
 
 #include <avr/wdt.h>
 
-#include "cpu.h"
+#include "irq.h"
+#include "periph/pm.h"
 
-void reboot(void)
+void pm_reboot(void)
 {
     /*
      * Since the AVR doesn't support a real software reset, we set the Watchdog