ACPI: LPSS: Use ACPI_COMPANION() directly

The ACPI_HANDLE() macro returns the ACPI handle of the ACPI device
object returned by the ACPI_COMPANION() macro, so it is more
straightforward to call the latter directly instead of passing
the handle produced by the former to acpi_bus_get_device().

Modify the code accordingly (no intentional functional impact).
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>

drivers/acpi/acpi_lpss.c

@@ -712,14 +712,13 @@ static void __lpss_reg_write(u32 val, struct lpss_private_data *pdata,
 
 static int lpss_reg_read(struct device *dev, unsigned int reg, u32 *val)
 {
-	struct acpi_device *adev;
+	struct acpi_device *adev = ACPI_COMPANION(dev);
 	struct lpss_private_data *pdata;
 	unsigned long flags;
 	int ret;
 
-	ret = acpi_bus_get_device(ACPI_HANDLE(dev), &adev);
-	if (WARN_ON(ret))
-		return ret;
+	if (WARN_ON(!adev))
+		return -ENODEV;
 
 	spin_lock_irqsave(&dev->power.lock, flags);
 	if (pm_runtime_suspended(dev)) {
@@ -732,6 +731,7 @@ static int lpss_reg_read(struct device *dev, unsigned int reg, u32 *val)
 		goto out;
 	}
 	*val = __lpss_reg_read(pdata, reg);
+	ret = 0;
 
  out:
 	spin_unlock_irqrestore(&dev->power.lock, flags);
@@ -1266,7 +1266,8 @@ static int acpi_lpss_platform_notify(struct notifier_block *nb,
 	if (!id || !id->driver_data)
 		return 0;
 
-	if (acpi_bus_get_device(ACPI_HANDLE(&pdev->dev), &adev))
+	adev = ACPI_COMPANION(&pdev->dev);
+	if (!adev)
 		return 0;
 
 	pdata = acpi_driver_data(adev);