aio: Replace zero-length array with flexible-array

There is a regular need in the kernel to provide a way to declare having a
dynamically sized set of trailing elements in a structure. Kernel code should
always use “flexible array members”[1] for these cases. The older style of
one-element or zero-length arrays should no longer be used[2].

[1] https://en.wikipedia.org/wiki/Flexible_array_member
[2] https://github.com/KSPP/linux/issues/21

Signed-off-by: Gustavo A. R. Silva <[e-mail]>

fs/aio.c

···
 	unsigned	header_length;	/* size of aio_ring */
 
 
-	struct io_event		io_events[0];
+	struct io_event		io_events[];
 }; /* 128 bytes + ring size */
 
 /*