Added available delete methods discovery during device probe, including the maximum sizes for said methods, which are used when processing BIO_DELETE requests. This includes updating UNMAP support discovery to be based on SBC-3 T10/1799-D Revision 31 specification.
Added available delete methods discovery during device probe, including the
maximum sizes for said methods, which are used when processing BIO_DELETE
requests. This includes updating UNMAP support discovery to be based on
SBC-3 T10/1799-D Revision 31 specification.

Added ATA TRIM support to cam scsi devices via ATA Pass-Through(16)

sys/cam/scsi/scsi_da.c:
        - Added ATA Data Set Management TRIM support via ATA Pass-Through(16)
          as a delete_method

        - Added four new probe states used to identity available methods and their
          limits for the processing of BIO_DELETE commands via both UNMAP and the
          new ATA TRIM commands.

        - Renamed Probe states to better indicate their use

        - Added delete method descriptions used when informing user of issues.

        - Added automatic calculation of the optimum delete mode based on which
          method presents the largest maximum request size as this is most likely
          to result in the best performance.

        - Added WRITE SAME max block limits

        - Updated UNMAP range generation to mirror that used by ATA TRIM, this
          optimises the generation of ranges and fixes a potential overflow
          issue in the count when combining multiple BIO_DELETE requests

        - Added output of warnings about short deletes. This should only ever
          be triggered on devices that fail to correctly advertise their supported
          delete modes / max sizes.

        - Fixed WS16 requests being incorrectly limited to 65535 in length.

Reviewed by:	mav
Approved by:	pjd (mentor)
MFC after:	2 weeks

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