Add note and daxio version to the vPMEM document
Add note and daxio version to the vPMEM document

Make the spec of virtual persistent memory consistent with
the contents of the admin manual, update the dependency of virtual
persistent memory about daxio, and add NOTE for the tested kernel
version.

Closes-Bug: #1894022

Change-Id: I30539bb47c98a588b95c066a394949d60af9c520

openstack/nova,mahak/nova,openstack/nova,mahak/nova,klmitch/nova,klmitch/nova,mahak/nova,klmitch/nova,openstack/nova,klmitch/nova