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>

drivers/net/wan/farsync.c

@@ -19,6 +19,7 @@
 #include <linux/kernel.h>
 #include <linux/version.h>
 #include <linux/pci.h>
+#include <linux/sched.h>
 #include <linux/ioport.h>
 #include <linux/init.h>
 #include <linux/if.h>