pc-testdev: remove useless cpu_to_le64/le64_to_cpu

So far the device was only used on little-endian machines.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Anthony Liguori <aliguori@us.ibm.com>
Message-id: 1374501278-31549-18-git-send-email-pbonzini@redhat.com
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>