ACPI: Introduce has_acpi_companion()

Now that the ACPI companions of devices are represented by pointers
to struct fwnode_handle, it is not quite efficient to check whether
or not an ACPI companion of a device is present by evaluating the
ACPI_COMPANION() macro.

For this reason, introduce a special static inline routine for that,
has_acpi_companion(), and update the code to use it where applicable.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
diff --git a/drivers/acpi/glue.c b/drivers/acpi/glue.c
index f774c65..39c485b 100644
--- a/drivers/acpi/glue.c
+++ b/drivers/acpi/glue.c
@@ -168,7 +168,7 @@
 	unsigned int node_id;
 	int retval = -EINVAL;
 
-	if (ACPI_COMPANION(dev)) {
+	if (has_acpi_companion(dev)) {
 		if (acpi_dev) {
 			dev_warn(dev, "ACPI companion already set\n");
 			return -EINVAL;
@@ -220,7 +220,7 @@
 	list_add(&physical_node->node, physnode_list);
 	acpi_dev->physical_node_count++;
 
-	if (!ACPI_COMPANION(dev))
+	if (!has_acpi_companion(dev))
 		ACPI_COMPANION_SET(dev, acpi_dev);
 
 	acpi_physnode_link_name(physical_node_name, node_id);