MFC r277917 (by ken), r278598:

MFC r277917 (by ken), r278598:
Improve SCSI Extended Inquiry VPD page (0x86) support.

sys/cam/scsi/scsi_all.h:
        In struct scsi_extended_inquiry_data:
        - Increase the length field to 2 bytes, as it is 2 bytes in SPC-4.
        - Add bit definitions for the various Activiate Microcode actions.
        - Add the Sequential Access Logical Block Protection support bit,
          since we need that in the sa(4) driver.  (For modifications
          that will come later.)
        - Add definitions for the various Multi I_T Nexus Microcode
          Download modes.

sys/cam/ctl/ctl.c:
        As of SPC-4, a single report of "REPORTED LUNS DATA HAS CHANGED"
        is to be given per I_T nexus.  Once it is reported, the unit
        attention condition should be cleared for all LUNS attached to
        an I_T nexus.

        Previously that only happened when a REPORT LUNS command was
        processed.

        This behavior may be different (according to SAM-5) when the
        UA_INTLCK_CTRL bits are non-zero in the control mode page but
        CTL does not currently support that.

        So, in view of the spec, whenever we report a LUN inventory
        change unit attention, clear it on all LUNs for that
        particular I_T nexus.

        Add a new function, ctl_clear_ua() that will clear a unit
        attention on all LUNs for the given I_T nexus.

        One field in the extended inquiry data that we could potentially
        report at some point is the maximum supported sense data length.
        To do that, we would the SIM to report (via path inquiry
        perhaps) how much sense data it is able to send.

        Add comments to explain some of the bits that are set in the
        Extended Inquiry VPD page.

        Add a few comments to make it more clear which functions handle
        various VPD pages.

git-svn-id: svn://svn.freebsd.org/base/stable/10@278796 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f