MFC r233746:

MFC r233746:
Be more conservative in using READ CAPACITY(16) command. Previous code
checked PROTECT bit in INQUIRY data for all SPC devices, while it is defined
only since SPC-3. But there are some SPC-2 USB devices were reported, that
have PROTECT bit set, return no error for READ CAPACITY(16) command, but
return wrong sector count value in response.

git-svn-id: svn://svn.freebsd.org/base/stable/9@233828 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f