cpu: x86: adapt to periph/pm

cpu/x86/Makefile.include

@@ -1,2 +1,3 @@
 export USEMODULE += quad_math
+export USEMODULE += periph_common
 export USEPKG += tlsf

cpu/x86/x86_reboot.c

@@ -33,6 +33,7 @@
 #include "x86_interrupts.h"
 #include "x86_ports.h"
 #include "x86_reboot.h"
+#include "periph/pm.h"
 
 #define KBC_DATA    (0x60)
 #define KBC_STATUS  (0x64)
@@ -86,7 +87,7 @@ void NORETURN x86_kbc_reboot(void)
 static x86_reboot_t reboot_fun;
 static bool reboot_twice;
 
-void reboot(void)
+void pm_reboot(void)
 {
     __asm__ volatile ("cli");
     if (!reboot_twice) {
@@ -98,6 +99,11 @@ void reboot(void)
     x86_kbc_reboot();
 }
 
+void pm_off(void)
+{
+    x86_shutdown();
+}
+
 void x86_set_reboot_fun(x86_reboot_t fun)
 {
     reboot_fun = fun;