Drivers: hv: vmbus: Fix harmless building warnings without CONFIG_PM_SLEEP

If CONFIG_PM_SLEEP is not set, we can comment out these functions to avoid
the below warnings:

drivers/hv/vmbus_drv.c:2208:12: warning: ‘vmbus_bus_resume’ defined but not used [-Wunused-function]
drivers/hv/vmbus_drv.c:2128:12: warning: ‘vmbus_bus_suspend’ defined but not used [-Wunused-function]
drivers/hv/vmbus_drv.c:937:12: warning: ‘vmbus_resume’ defined but not used [-Wunused-function]
drivers/hv/vmbus_drv.c:918:12: warning: ‘vmbus_suspend’ defined but not used [-Wunused-function]

Fixes: 271b2224 ("Drivers: hv: vmbus: Implement suspend/resume for VSC drivers for hibernation")
Fixes: f53335e3 ("Drivers: hv: vmbus: Suspend/resume the vmbus itself for hibernation")
Reported-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Dexuan Cui <decui@microsoft.com>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

drivers/hv/vmbus_drv.c

@@ -912,6 +912,7 @@ static void vmbus_shutdown(struct device *child_device)
 		drv->shutdown(dev);
 }
 
+#ifdef CONFIG_PM_SLEEP
 /*
  * vmbus_suspend - Suspend a vmbus device
  */
@@ -949,6 +950,7 @@ static int vmbus_resume(struct device *child_device)
 
 	return drv->resume(dev);
 }
+#endif /* CONFIG_PM_SLEEP */
 
 /*
  * vmbus_device_release - Final callback release of the vmbus child device
@@ -1070,6 +1072,7 @@ void vmbus_on_msg_dpc(unsigned long data)
 	vmbus_signal_eom(msg, message_type);
 }
 
+#ifdef CONFIG_PM_SLEEP
 /*
  * Fake RESCIND_CHANNEL messages to clean up hv_sock channels by force for
  * hibernation, because hv_sock connections can not persist across hibernation.
@@ -1105,6 +1108,7 @@ static void vmbus_force_channel_rescinded(struct vmbus_channel *channel)
 		      vmbus_connection.work_queue,
 		      &ctx->work);
 }
+#endif /* CONFIG_PM_SLEEP */
 
 /*
  * Direct callback for channels using other deferred processing
@@ -2125,6 +2129,7 @@ static int vmbus_acpi_add(struct acpi_device *device)
 	return ret_val;
 }
 
+#ifdef CONFIG_PM_SLEEP
 static int vmbus_bus_suspend(struct device *dev)
 {
 	struct vmbus_channel *channel, *sc;
@@ -2247,6 +2252,7 @@ static int vmbus_bus_resume(struct device *dev)
 
 	return 0;
 }
+#endif /* CONFIG_PM_SLEEP */
 
 static const struct acpi_device_id vmbus_acpi_device_ids[] = {
 	{"VMBUS", 0},