Merge remote-tracking branch 'remotes/sstabellini/tags/xen-220615-3' into staging

xen-220615, more SOB lines

# gpg: Signature made Tue Jun 23 17:19:08 2015 BST using RSA key ID 70E1AE90
# gpg: Good signature from "Stefano Stabellini <stefano.stabellini@eu.citrix.com>"

* remotes/sstabellini/tags/xen-220615-3:
  Revert "xen-hvm: increase maxmem before calling xc_domain_populate_physmap"
  xen/pass-through: constify some static data
  xen/pass-through: log errno values rather than function return ones
  xen/pass-through: ROM BAR handling adjustments
  xen/pass-through: fold host PCI command register writes

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>