Revert "aio: fix kernel memory disclosure in io_getevents() introduced in v3.10"

This reverts commit 0e2e24e5, which
was applied twice mistakenly. The first one is
bee3f7b8.
Reported-by: Gu Zheng <guz.fnst@cn.fujitsu.com>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Benjamin LaHaise <bcrl@kvack.org>
Cc: Mateusz Guzik <mguzik@redhat.com>
Cc: Petr Matousek <pmatouse@redhat.com>
Cc: Kent Overstreet <kmo@daterainc.com>
Cc: Jeff Moyer <jmoyer@redhat.com>

fs/aio.c

@@ -1066,9 +1066,6 @@ static long aio_read_events_ring(struct kioctx *ctx,
 	head %= ctx->nr_events;
 	tail %= ctx->nr_events;
 
-	head %= ctx->nr_events;
-	tail %= ctx->nr_events;
-
 	while (ret < nr) {
 		long avail;
 		struct io_event *ev;