KVM: x86: wean fast IN from emulator_pio_in

Use __emulator_pio_in() directly for fast PIO instead of bouncing through
emulator_pio_in() now that __emulator_pio_in() fills "val" when handling
in-kernel PIO.  vcpu->arch.pio.count is guaranteed to be '0', so this a
pure nop.

emulator_pio_in_emulated is now the last caller of emulator_pio_in.

No functional change intended.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/x86/kvm/x86.c

@@ -8886,7 +8886,7 @@ static int kvm_fast_pio_in(struct kvm_vcpu *vcpu, int size,
 	/* For size less than 4 we merge, else we zero extend */
 	val = (size < 4) ? kvm_rax_read(vcpu) : 0;
 
-	ret = emulator_pio_in(vcpu, size, port, &val, 1);
+	ret = __emulator_pio_in(vcpu, size, port, &val, 1);
 	if (ret) {
 		kvm_rax_write(vcpu, val);
 		return ret;