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/wireless/hostap/hostap_info.c b/drivers/net/wireless/hostap/hostap_info.c
index 6fa14a4..4dfb40a 100644
--- a/drivers/net/wireless/hostap/hostap_info.c
+++ b/drivers/net/wireless/hostap/hostap_info.c
@@ -1,6 +1,7 @@
 /* Host AP driver Info Frame processing (part of hostap.o module) */
 
 #include <linux/if_arp.h>
+#include <linux/sched.h>
 #include "hostap_wlan.h"
 #include "hostap.h"
 #include "hostap_ap.h"