MFC r220602:

MFC r220602:
Improve SATA Asynchronous Notification feature support in CAM:
 - make SATA SIMs announce capabilities to handle SDB with Notification bit;
 - make PMP driver honor this SIMs capability;
 - make SATA XPT to negotiate and enable this feature for ATAPI devices.

This feature allows supporting SATA ATAPI devices to inform system about
some events happened, that may require attention. In my case this allows
LG GH22LS50 SATA DVR-RW drive to report tray open/close events. Events
reported to CAM in form of AC_SCSI_AEN async. Further they could be used
as a hints for checking device status and reporting media change to upper
layers, for example, via spoiling mechanism of GEOM.

git-svn-id: svn://svn.freebsd.org/base/stable/8@220861 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f