qemu: Simplify size check for ppc64 NVDIMMs
qemu: Simplify size check for ppc64 NVDIMMs

We already calculated the guest area, which is what is subject
to minimum size requirements, a few lines earlier.

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

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