ACPICA: _OSI Support: handle any errors from acpi_os_acquire_mutex()

Check for any errors. Handles possible timeout case if
ACPI_WAIT_FOREVER is changed to be less than "forever".
Jung-uk Kim.

Signed-off-by: Jung-uk Kim <jkim@FreeBSD.org>
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>