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/drivers/acpi/acpi_platform.c b/drivers/acpi/acpi_platform.c
index 1284138..4bf7559 100644
--- a/drivers/acpi/acpi_platform.c
+++ b/drivers/acpi/acpi_platform.c
@@ -102,7 +102,7 @@
 	pdevinfo.id = -1;
 	pdevinfo.res = resources;
 	pdevinfo.num_res = count;
-	pdevinfo.acpi_node.companion = adev;
+	pdevinfo.fwnode = acpi_fwnode_handle(adev);
 	pdevinfo.dma_mask = DMA_BIT_MASK(32);
 	pdev = platform_device_register_full(&pdevinfo);
 	if (IS_ERR(pdev))