MFV r272493:

Show individual disk capacity when doing zpool list -v.

Illumos issue:
    5147 zpool list -v should show individual disk capacity

MFC after:	1 week


git-svn-id: svn+ssh://svn.freebsd.org/base/head@272502 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f