qemuBuildIOMMUCommandLine: Generate via JSON
qemuBuildIOMMUCommandLine: Generate via JSON

QEMU declares the following types for fields we control:

  intremap=<OnOffAuto>   - on/off/auto (default: "auto")
  caching-mode=<bool>    -  (default: false)
  eim=<OnOffAuto>        - on/off/auto (default: "auto")
  device-iotlb=<bool>    -  (default: false)
  aw-bits=<uint8>        -  (default: 39)

Signed-off-by: Peter Krempa <2cf5c04c61aa466e4a47bfedc747d17279c72ffc@redhat.com>
Reviewed-by: Ján Tomko <4cab11cfb98d3c937327354a78eb07dbb6ee2bc6@redhat.com>

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