vfs: 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 vfs at all.

So, remove the unused hardirq.h.
Signed-off-by: Yang Shi <yang.s@alibaba-inc.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

fs/dcache.c

@@ -32,7 +32,6 @@
 #include <linux/swap.h>
 #include <linux/bootmem.h>
 #include <linux/fs_struct.h>
-#include <linux/hardirq.h>
 #include <linux/bit_spinlock.h>
 #include <linux/rculist_bl.h>
 #include <linux/prefetch.h>

fs/file_table.c

@@ -23,7 +23,6 @@
 #include <linux/sysctl.h>
 #include <linux/percpu_counter.h>
 #include <linux/percpu.h>
-#include <linux/hardirq.h>
 #include <linux/task_work.h>
 #include <linux/ima.h>
 #include <linux/swap.h>