ACPI: bus: Constify acpi_companion_match() returned value

acpi_companion_match() doesn't alter the contents of the passed
parameter, so we don't expect that returned value can be altered
either. So constify it.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/acpi/bus.c

@@ -682,7 +682,7 @@ bool acpi_device_is_first_physical_node(struct acpi_device *adev,
  * resources available from it but they will be matched normally using functions
  * provided by their bus types (and analogously for their modalias).
  */
-struct acpi_device *acpi_companion_match(const struct device *dev)
+const struct acpi_device *acpi_companion_match(const struct device *dev)
 {
 	struct acpi_device *adev;
 
@@ -706,7 +706,7 @@ struct acpi_device *acpi_companion_match(const struct device *dev)
  * identifiers and a _DSD object with the "compatible" property, use that
  * property to match against the given list of identifiers.
  */
-static bool acpi_of_match_device(struct acpi_device *adev,
+static bool acpi_of_match_device(const struct acpi_device *adev,
 				 const struct of_device_id *of_match_table,
 				 const struct of_device_id **of_id)
 {
@@ -808,7 +808,7 @@ static bool __acpi_match_device_cls(const struct acpi_device_id *id,
 	return true;
 }
 
-static bool __acpi_match_device(struct acpi_device *device,
+static bool __acpi_match_device(const struct acpi_device *device,
 				const struct acpi_device_id *acpi_ids,
 				const struct of_device_id *of_ids,
 				const struct acpi_device_id **acpi_id,

drivers/acpi/device_sysfs.c

@@ -283,7 +283,7 @@ int acpi_device_uevent_modalias(const struct device *dev, struct kobj_uevent_env
 }
 EXPORT_SYMBOL_GPL(acpi_device_uevent_modalias);
 
-static int __acpi_device_modalias(struct acpi_device *adev, char *buf, int size)
+static int __acpi_device_modalias(const struct acpi_device *adev, char *buf, int size)
 {
 	int len, count;
 

drivers/acpi/internal.h

@@ -119,7 +119,7 @@ int acpi_bus_register_early_device(int type);
 /* --------------------------------------------------------------------------
                      Device Matching and Notification
    -------------------------------------------------------------------------- */
-struct acpi_device *acpi_companion_match(const struct device *dev);
+const struct acpi_device *acpi_companion_match(const struct device *dev);
 int __acpi_device_uevent_modalias(const struct acpi_device *adev,
 				  struct kobj_uevent_env *env);