Preempt counter APIs have been split out, currently, hardirq.h just
includes irq_enter/exit APIs which are not used by TIPC at all.
So, remove the unused hardirq.h.
Signed-off-by: Yang Shi <yang.s@alibaba-inc.com> Acked-by: Ying Xue <ying.xue@windriver.com> Tested-by: Ying Xue <ying.xue@windriver.com> Cc: Jon Maloy <jon.maloy@ericsson.com> Cc: "David S. Miller" <davem@davemloft.net> Signed-off-by: David S. Miller <davem@davemloft.net>