ACPICA: Add an error message if the Debugger fails initialization.

Previously, only status was returned.

Linux kernel behaviour is not affected as the changes only apply to the
debugger which is currently not shipped in the kernel.

Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Lv Zheng <lv.zheng@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>