s390x/tcg: switch to new SIGP handling code

This effectively enables experimental SMP support. Floating interrupts are
still a mess, so allow it but print a big warning. There also seems
to be a problem with CPU hotplug (after the main loop started).

Signed-off-by: David Hildenbrand <david@redhat.com>
Message-Id: <20170928203708.9376-27-david@redhat.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
[CH: changed insn-data.def as pointed out by Richard]
Signed-off-by: Cornelia Huck <cohuck@redhat.com>
