epoll: use real type instead of void *

eventpoll.c uses void * in one place for no obvious reason; change it to
use the real type instead.
Signed-off-by: Tony Battersby <tonyb@cybernetics.com>
Acked-by: Davide Libenzi <davidel@xmailserver.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs/eventpoll.c

@@ -192,7 +192,7 @@ struct eppoll_entry {
 	struct list_head llink;
 
 	/* The "base" pointer is set to the container "struct epitem" */
-	void *base;
+	struct epitem *base;
 
 	/*
 	 * Wait queue item that will be linked to the target file wait