kernel/notifier.c should #include <linux/reboot.h>

Every file should include the headers containing the prototypes for its global
functions (in this case {,un}register_reboot_notifier()).
Signed-off-by: Adrian Bunk <bunk@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

kernel/notifier.c

@@ -4,6 +4,7 @@
 #include <linux/notifier.h>
 #include <linux/rcupdate.h>
 #include <linux/vmalloc.h>
+#include <linux/reboot.h>
 
 /*
  *	Notifier list for kernel code which wants to be called