qtest/irq: Rework IRQ interception

qtest/irq: Rework IRQ interception

Change the qtest intercept handler to accept just the individual IRQ
being intercepted as opaque. n is still expected to be correctly set
as for the original intercepted irq. qemu_intercept_irq_in is updated
accordingly.

Then covert the qemu_irq_intercept_out call to use qdev intercept
version. This stops qtest from having to mess with the raw IRQ pointers
(still has to mess with names and counts but a step in the right
direction).

Reviewed-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Peter Crosthwaite <peter.crosthwaite@xilinx.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>