ACPI / PM: Move processor suspend/resume to syscore_ops

The system suspend routine of the ACPI processor driver saves
the BUS_MASTER_RLD register and its resume routine restores it.
However, there can be only one such register in the system and it
really should be saved after non-boot CPUs have been offlined and
restored before they are put back online during resume.

For this reason, move the saving and restoration of BUS_MASTER_RLD
to syscore suspend and syscore resume, respectively, and drop the no
longer necessary suspend/resume callbacks from the ACPI processor
driver.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c
index f0df2c9..eb133c7 100644
--- a/drivers/acpi/processor_idle.c
+++ b/drivers/acpi/processor_idle.c
@@ -34,6 +34,7 @@
 #include <linux/sched.h>       /* need_resched() */
 #include <linux/clockchips.h>
 #include <linux/cpuidle.h>
+#include <linux/syscore_ops.h>
 
 /*
  * Include the apic definitions for x86 to have the APIC timer related defines
@@ -210,33 +211,41 @@
 
 #endif
 
+#ifdef CONFIG_PM_SLEEP
 static u32 saved_bm_rld;
 
-static void acpi_idle_bm_rld_save(void)
+int acpi_processor_suspend(void)
 {
 	acpi_read_bit_register(ACPI_BITREG_BUS_MASTER_RLD, &saved_bm_rld);
+	return 0;
 }
-static void acpi_idle_bm_rld_restore(void)
+
+void acpi_processor_resume(void)
 {
 	u32 resumed_bm_rld;
 
 	acpi_read_bit_register(ACPI_BITREG_BUS_MASTER_RLD, &resumed_bm_rld);
+	if (resumed_bm_rld == saved_bm_rld)
+		return;
 
-	if (resumed_bm_rld != saved_bm_rld)
-		acpi_write_bit_register(ACPI_BITREG_BUS_MASTER_RLD, saved_bm_rld);
+	acpi_write_bit_register(ACPI_BITREG_BUS_MASTER_RLD, saved_bm_rld);
 }
 
-int acpi_processor_suspend(struct device *dev)
+static struct syscore_ops acpi_processor_syscore_ops = {
+	.suspend = acpi_processor_suspend,
+	.resume = acpi_processor_resume,
+};
+
+void acpi_processor_syscore_init(void)
 {
-	acpi_idle_bm_rld_save();
-	return 0;
+	register_syscore_ops(&acpi_processor_syscore_ops);
 }
 
-int acpi_processor_resume(struct device *dev)
+void acpi_processor_syscore_exit(void)
 {
-	acpi_idle_bm_rld_restore();
-	return 0;
+	unregister_syscore_ops(&acpi_processor_syscore_ops);
 }
+#endif /* CONFIG_PM_SLEEP */
 
 #if defined(CONFIG_X86)
 static void tsc_check_state(int state)