headers: smp_lock.h redux

* Remove smp_lock.h from files which don't need it (including some headers!)
* Add smp_lock.h to files which do need it
* Make smp_lock.h include conditional in hardirq.h
  It's needed only for one kernel_locked() usage which is under CONFIG_PREEMPT

  This will make hardirq.h inclusion cheaper for every PREEMPT=n config
  (which includes allmodconfig/allyesconfig, BTW)

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/drivers/isdn/hisax/hfc_usb.c b/drivers/isdn/hisax/hfc_usb.c
index 8df889b..9de5420 100644
--- a/drivers/isdn/hisax/hfc_usb.c
+++ b/drivers/isdn/hisax/hfc_usb.c
@@ -37,7 +37,6 @@
 #include <linux/kernel_stat.h>
 #include <linux/usb.h>
 #include <linux/kernel.h>
-#include <linux/smp_lock.h>
 #include <linux/sched.h>
 #include <linux/moduleparam.h>
 #include "hisax.h"
diff --git a/drivers/isdn/i4l/isdn_tty.c b/drivers/isdn/i4l/isdn_tty.c
index b4d4522..2881a66 100644
--- a/drivers/isdn/i4l/isdn_tty.c
+++ b/drivers/isdn/i4l/isdn_tty.c
@@ -13,6 +13,7 @@
 
 #include <linux/isdn.h>
 #include <linux/delay.h>
+#include <linux/smp_lock.h>
 #include "isdn_common.h"
 #include "isdn_tty.h"
 #ifdef CONFIG_ISDN_AUDIO
diff --git a/drivers/isdn/mISDN/stack.c b/drivers/isdn/mISDN/stack.c
index e2f4501..3e1532a 100644
--- a/drivers/isdn/mISDN/stack.c
+++ b/drivers/isdn/mISDN/stack.c
@@ -17,6 +17,7 @@
 
 #include <linux/mISDNif.h>
 #include <linux/kthread.h>
+#include <linux/smp_lock.h>
 #include "core.h"
 
 static u_int	*debug;