pci: add pci test device

This adds a new device that we can use for testing PCI PIO and MMIO, with and
without ioeventfd in different configurations.  FAST_MMIO will be added if/when
kvm supports it.  Also included are minor cleanups in kvm APIs that it needs.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

# gpg: Signature made Mon 15 Apr 2013 05:42:24 PM CDT using RSA key ID D28D5469
# gpg: Can't check signature: public key not found

# By Michael S. Tsirkin
# Via Michael S. Tsirkin
* mst/tags/for_anthony:
  pci: add pci test device
  kvm: support non datamatch ioeventfd
  kvm: support any size for pio eventfd
  kvm: remove unused APIs

Message-id: cover.1366272004.git.mst@redhat.com
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>