formatdomain.html.in: mention pSeries NVDIMM 'align down' mechanic
formatdomain.html.in: mention pSeries NVDIMM 'align down' mechanic

The reason why we align down the guest area (total-size - label-size) is
explained in the body of qemuDomainNVDimmAlignSizePseries(). This
behavior must also be documented in the user docs.

Signed-off-by: Daniel Henrique Barboza <627b089ad62deae9aaf06ccfa2c9056df28927e0@gmail.com>
Reviewed-by: Andrea Bolognani <3ada0bee826c753786fdbba72243dfba997094cf@redhat.com>

nertpinx/libvirt,crobinso/libvirt,olafhering/libvirt,libvirt/libvirt,nertpinx/libvirt,jfehlig/libvirt,crobinso/libvirt,olafhering/libvirt,nertpinx/libvirt,nertpinx/libvirt,libvirt/libvirt,zippy2/libvirt,libvirt/libvirt,zippy2/libvirt,jardasgit/libvirt,crobinso/libvirt,libvirt/libvirt,crobinso/libvirt,olafhering/libvirt,jardasgit/libvirt,jardasgit/libvirt,olafhering/libvirt,jfehlig/libvirt,zippy2/libvirt,jardasgit/libvirt,jardasgit/libvirt,nertpinx/libvirt,jfehlig/libvirt,zippy2/libvirt,jfehlig/libvirt