btrfs: remove unused hardirq.h

Preempt counter APIs have been split out, currently, hardirq.h just
includes irq_enter/exit APIs which are not used by btrfs at all.

So, remove the unused hardirq.h.

Signed-off-by: Yang Shi <yang.s@alibaba-inc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
Yang Shi 2017-11-18 07:02:16 +08:00 • committed by David Sterba
commit 86d750a48a