x86/hpet: force_hpet_broadcast can be __initdata

Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>

--- a/xen/arch/x86/hpet.c
+++ b/xen/arch/x86/hpet.c
@@ -57,7 +57,7 @@ unsigned long __read_mostly hpet_address
  * if RTC interrupts are enabled. Enable this option if want to always enable
  * legacy hpet broadcast for deep C state
  */
-static bool_t __read_mostly force_hpet_broadcast;
+static bool_t __initdata force_hpet_broadcast;
 boolean_param("hpetbroadcast", force_hpet_broadcast);
 
 /*