This needs to be a unique interrupt source because we do
not have a register or similar to poll to make sure the
IRQ is really for us.  We do not have any dev_id to pass
in anyways, and the generic IRQ layer is now enforcing
that when SA_SHIRQ is specified, dev_id must be non-NULL.
Signed-off-by: David S. Miller <davem@davemloft.net>