KVM: Clean up kvm_setup_pio()

Split kvm_setup_pio() into two functions, one to setup in/out pio
(kvm_emulate_pio()) and one to setup ins/outs pio (kvm_emulate_pio_string()).

Signed-off-by: Laurent Vivier <Laurent.Vivier@bull.net>
Signed-off-by: Avi Kivity <avi@qumranet.com>