When changing ring size, we free all memory including status block
memory.  If we're in INTA mode and sharing IRQ, the IRQ handler can
be called and it will reference the NULL status block pointer.

Because of the lockless design of the IRQ handler, there is no simple
way to synchronize and prevent this.  So we avoid this problem by
freeing the IRQ handler before freeing the status block memory.
Signed-off-by: NMichael Chan <mchan@broadcom.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>