ACPI / hotplug / PCI: Drop redundant checks from check_hotplug_bridge()

Two checks in check_hotplug_bridge() are redundant (they have been
done by the caller already), so drop them.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>