[PATCH] add bottom_half.h

With CONFIG_SMP=n:

  drivers/input/ff-memless.c:384: warning: implicit declaration of function 'local_bh_disable'
  drivers/input/ff-memless.c:393: warning: implicit declaration of function 'local_bh_enable'

Really linux/spinlock.h should include linux/interrupt.h.  But interrupt.h
includes sched.h which will need spinlock.h.

So the patch breaks the _bh declarations out into a separate header and
includes it in both interrupt.h and spinlock.h.

Cc: "Randy.Dunlap" <rdunlap@xenotime.net>
Cc: Andi Kleen <ak@suse.de>
Cc: <stable@kernel.org>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/include/linux/spinlock.h b/include/linux/spinlock.h
index 8451052..94b767d 100644
--- a/include/linux/spinlock.h
+++ b/include/linux/spinlock.h
@@ -52,6 +52,7 @@
 #include <linux/thread_info.h>
 #include <linux/kernel.h>
 #include <linux/stringify.h>
+#include <linux/bottom_half.h>
 
 #include <asm/system.h>