kvm: Correct documentation of kvm_irqchip_*()

kvm: Correct documentation of kvm_irqchip_*()

When split irqchip support was introduced, the meaning of
kvm_irqchip_in_kernel() changed: now it only means the LAPIC is
in kernel.  The PIC, IOAPIC, and PIT might be in userspace if
irqchip=split was set.  Update the doc comment to reflect that.

While at it, remove the "the user asked us" part in
kvm_irqchip_is_split() doc comment.  That macro has nothing to do
with existence of explicit user-provided options.

Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20200922203612.2178370-1-ehabkost@redhat.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>