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/net/irda/irnet/irnet_ppp.c b/net/irda/irnet/irnet_ppp.c
index 68cbcb1..7dea882 100644
--- a/net/irda/irnet/irnet_ppp.c
+++ b/net/irda/irnet/irnet_ppp.c
@@ -13,6 +13,7 @@
  *	2) as a control channel (write commands, read events)
  */
 
+#include <linux/sched.h>
 #include <linux/smp_lock.h>
 #include "irnet_ppp.h"		/* Private header */
 /* Please put other headers in irnet.h - Thanks */