MFc r228846:

MFc r228846:
Use READ CAPACITY(16) to get information about device physical sectors.
As soon as not all devices support READ CAPACITY(16), automatically fall
back to READ CAPACITY(10) if CAM_REQ_INVALID or SSD_KEY_ILLEGAL_REQUEST
status returned.

It also provides first bits of information about Logical Block Provisioning
(aka UNMAP/TRIM) support by the device.

git-svn-id: svn://svn.freebsd.org/base/stable/8@232942 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f