ACPI / hotplug: Simplify acpi_set_hp_context()

Since all of the acpi_set_hp_context() callers pass at least one NULL
function pointer and one caller passes NULL function pointers only
to it, drop function pointer arguments from acpi_set_hp_context()
and make the callers initialize the function pointers in struct
acpi_hotplug_context by themselves before passing it to
acpi_set_hp_context().

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index f775fa0..3ffc930 100644
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -77,7 +77,9 @@
 				void (*uevent)(struct acpi_device *, u32))
 {
 	acpi_lock_hp_context();
-	acpi_set_hp_context(adev, hp, notify, uevent, NULL);
+	hp->notify = notify;
+	hp->uevent = uevent;
+	acpi_set_hp_context(adev, hp);
 	acpi_unlock_hp_context();
 }
 EXPORT_SYMBOL_GPL(acpi_initialize_hp_context);