Revert "KVM: Don't accept obviously wrong gsi values via KVM_IRQFD"

This reverts commit 36ae3c0a

.

The commit broke compilation on !CONFIG_HAVE_KVM_IRQ_ROUTING. Also,
there may be cases with CONFIG_HAVE_KVM_IRQ_ROUTING, where larger
gsi values make sense.

As the commit was meant as an early indicator to user space that
something is wrong, reverting just restores the previous behavior
where overly large values are ignored when encountered (without
any direct feedback).

Reported-by: Abdul Haleem <abdhalee@linux.vnet.ibm.com>
Signed-off-by: Jan H. Schönherr <jschoenh@amazon.de>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>