driver core / ACPI: Represent ACPI companions using fwnode_handle

Now that we have struct fwnode_handle, we can use that to point to
ACPI companions from struct device objects instead of pointing to
struct acpi_device directly.

There are two benefits from that.  First, the somewhat ugly and
hackish struct acpi_dev_node can be dropped and, second, the same
struct fwnode_handle pointer can be used in the future to point
to other (non-ACPI) firmware device node types.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Grant Likely <grant.likely@linaro.org>
diff --git a/include/linux/device.h b/include/linux/device.h
index 0eb8ee2..badef20 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -38,6 +38,7 @@
 struct subsys_private;
 struct bus_type;
 struct device_node;
+struct fwnode_handle;
 struct iommu_ops;
 struct iommu_group;
 
@@ -650,14 +651,6 @@
 	unsigned long segment_boundary_mask;
 };
 
-struct acpi_device;
-
-struct acpi_dev_node {
-#ifdef CONFIG_ACPI
-	struct acpi_device *companion;
-#endif
-};
-
 /**
  * struct device - The basic device structure
  * @parent:	The device's "parent" device, the device to which it is attached.
@@ -703,7 +696,7 @@
  * @cma_area:	Contiguous memory area for dma allocations
  * @archdata:	For arch-specific additions.
  * @of_node:	Associated device tree node.
- * @acpi_node:	Associated ACPI device node.
+ * @fwnode:	Associated device node supplied by platform firmware.
  * @devt:	For creating the sysfs "dev".
  * @id:		device instance
  * @devres_lock: Spinlock to protect the resource of the device.
@@ -779,7 +772,7 @@
 	struct dev_archdata	archdata;
 
 	struct device_node	*of_node; /* associated device tree node */
-	struct acpi_dev_node	acpi_node; /* associated ACPI device node */
+	struct fwnode_handle	*fwnode; /* firmware device node */
 
 	dev_t			devt;	/* dev_t, creates the sysfs "dev" */
 	u32			id;	/* device instance */