Added the hmp command to query io apic state, may be usefull after guest
crashes to understand IRQ routing in guest.

Implementation is only for kvm here. The dump will look like
(qemu) info ioapic
ioapic id=0x00 sel=0x26 (redir[11])
pin 0  0x0000000000010000 dest=0 vec=0   active-hi edge  masked fixed  physical
pin 1  0x0000000000000031 dest=0 vec=49  active-hi edge         fixed  physical
...
pin 23 0x0000000000010000 dest=0 vec=0   active-hi edge  masked fixed  physical
IRR        (none)
Remote IRR (none)

Signed-off-by: Pavel Butsykin <pbutsykin@virtuozzo.com>
Signed-off-by: Denis V. Lunev <den@openvz.org>
CC: Paolo Bonzini <pbonzini@redhat.com>
CC: Andreas Färber <afaerber@suse.de>
Message-Id: <1442927901-1084-9-git-send-email-den@openvz.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>