epoll: fix size check in epoll_create()

Fix a size check WRT the manual pages.  This was inadvertently broken by
commit 9fe5ad9c8c ("flag parameters
add-on: remove epoll_create size param").

Signed-off-by: Davide Libenzi <davidel@xmailserver.org>
Cc: <Hiroyuki.Mach@gmail.com>
Cc: rohit verma <rohit.170309@gmail.com>
Cc: Ulrich Drepper <drepper@redhat.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs/eventpoll.c

@@ -1212,7 +1212,7 @@ SYSCALL_DEFINE1(epoll_create1, int, flags)
 
 SYSCALL_DEFINE1(epoll_create, int, size)
 {
-	if (size < 0)
+	if (size <= 0)
 		return -EINVAL;
 
 	return sys_epoll_create1(0);