eventpoll: Don't re-zero eventpoll fields

Remove redundant and unnecessary code.

ep_alloc uses kzalloc to create struct eventpoll, so there is no need to
set fields to defaults of 0. This was accidentally introduced in commit
85455c79 ("eventpoll: support busy poll per epoll instance") and
expanded on in follow-up commits.
Signed-off-by: Joe Damato <jdamato@fastly.com>
Link: https://lore.kernel.org/r/20240807105231.179158-1-jdamato@fastly.comReviewed-by: Martin Karsten <mkarsten@uwaterloo.ca>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>

fs/eventpoll.c

@@ -2200,11 +2200,6 @@ static int do_epoll_create(int flags)
 		error = PTR_ERR(file);
 		goto out_free_fd;
 	}
-#ifdef CONFIG_NET_RX_BUSY_POLL
-	ep->busy_poll_usecs = 0;
-	ep->busy_poll_budget = 0;
-	ep->prefer_busy_poll = false;
-#endif
 	ep->file = file;
 	fd_install(fd, file);
 	return fd;