kvmvapic: add ioport read accessor

Necessary since memory region accessor assumes read and write
methods are registered. Otherwise reading I/O port 0x7e segfaults.

https://bugzilla.redhat.com/show_bug.cgi?id=954306

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Reviewed-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Gleb Natapov <gleb@redhat.com>
Merge remote-tracking branch 'qemu-kvm/uq/master' into staging

# By Marcelo Tosatti
# Via Gleb Natapov
* qemu-kvm/uq/master:
  kvmvapic: add ioport read accessor

Message-id: cover.1367844188.git.gleb@redhat.com
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>