headers: remove sched.h from interrupt.h

After m68k's task_thread_info() doesn't refer to current,
it's possible to remove sched.h from interrupt.h and not break m68k!
Many thanks to Heiko Carstens for allowing this.

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
diff --git a/drivers/lguest/interrupts_and_traps.c b/drivers/lguest/interrupts_and_traps.c
index 1864818..daaf866 100644
--- a/drivers/lguest/interrupts_and_traps.c
+++ b/drivers/lguest/interrupts_and_traps.c
@@ -16,6 +16,7 @@
 #include <linux/uaccess.h>
 #include <linux/interrupt.h>
 #include <linux/module.h>
+#include <linux/sched.h>
 #include "lg.h"
 
 /* Allow Guests to use a non-128 (ie. non-Linux) syscall trap. */