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/net/appletalk/ddp.c b/net/appletalk/ddp.c
index 590b839..bfbe137 100644
--- a/net/appletalk/ddp.c
+++ b/net/appletalk/ddp.c
@@ -54,6 +54,7 @@
 #include <linux/capability.h>
 #include <linux/module.h>
 #include <linux/if_arp.h>
+#include <linux/smp_lock.h>
 #include <linux/termios.h>	/* For TIOCOUTQ/INQ */
 #include <net/datalink.h>
 #include <net/psnap.h>