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/hamachi.c b/drivers/net/hamachi.c
index 1d5064a..f7519a5 100644
--- a/drivers/net/hamachi.c
+++ b/drivers/net/hamachi.c
@@ -145,6 +145,7 @@
 /* Time in jiffies before concluding the transmitter is hung. */
 #define TX_TIMEOUT  (5*HZ)
 
+#include <linux/capability.h>
 #include <linux/module.h>
 #include <linux/kernel.h>
 #include <linux/string.h>