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/net/tokenring/ibmtr.c b/drivers/net/tokenring/ibmtr.c
index 525bbc5..36cb242 100644
--- a/drivers/net/tokenring/ibmtr.c
+++ b/drivers/net/tokenring/ibmtr.c
@@ -108,6 +108,7 @@
 #define IBMTR_DEBUG_MESSAGES 0
 
 #include <linux/module.h>
+#include <linux/sched.h>
 
 #ifdef PCMCIA		/* required for ibmtr_cs.c to build */
 #undef MODULE		/* yes, really */