ACPI: add dynamic_debug support

Commit 1a699476e258 ("ACPI / hotplug / PCI: Hotplug notifications
from acpi_bus_notify()") added debug messages for a few common
events. These debug messages are unconditionally enabled if
CONFIG_DYNAMIC_DEBUG is defined, contrary to the documented
meaning, making the ACPI system spew lots of unwanted noise on
any kernel with dynamic debugging.

The bug was introduced by commit fbfddae69657 ("ACPI: Add
acpi_handle_<level>() interfaces"), which added the
CONFIG_DYNAMIC_DEBUG dependency without respecting its meaning.

Fix by adding real support for dynamic_debug.

Fixes: fbfddae69657 ("ACPI: Add acpi_handle_<level>() interfaces")
Signed-off-by: Bjørn Mork <bjorn@mork.no>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Merge branch 'acpi-hotplug' into bleeding-edge

* acpi-hotplug:
  ACPI: add dynamic_debug support