s390x/kvm: use ioctl KVM_S390_IRQ for vcpu interrupts

KVM_S390_INT uses only two parameter fields. This is not
enough to pass all required information for certain interrupts.

A new ioctl KVM_S390_IRQ is available which allows us to
inject all local interrupts as defined in the Principles of
Operation. It takes a struct kvm_s390_irq as a parameter
which can store interrupt payload data for all interrupts.

Let's use the new ioctl for injecting vcpu interrupts.

Tested-by: Thomas Huth <thuth@linux.vnet.ibm.com>
Reviewed-by: Thomas Huth <thuth@linux.vnet.ibm.com>
Reviewed-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Jens Freimann <jfrei@linux.vnet.ibm.com>
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>