Merge branch 'stable/xen-pciback-0.6.3.bugfixes' of git://oss.oracle.com/git/kwilk...

Merge branch 'stable/xen-pciback-0.6.3.bugfixes' of git://oss.oracle.com/git/kwilk/xen into uek2-merge

* 'stable/xen-pciback-0.6.3.bugfixes' of git://oss.oracle.com/git/kwilk/xen:
  xen/pciback: Check if the device is found instead of blindly assuming so.
  xen/pciback: Do not dereference psdev during printk when it is NULL.
  xen/pciback: double lock typo
  xen/pciback: use mutex rather than spinlock in vpci backend
  xen/pciback: Use mutexes when working with Xenbus state transitions.
  xen/pciback: miscellaneous adjustments
  xen/pciback: use mutex rather than spinlock in passthrough backend
  xen/pciback: use resource_size()