libata: 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/21Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>

include/linux/libata.h

@@ -609,7 +609,7 @@ struct ata_host {
 	struct task_struct	*eh_owner;
 
 	struct ata_port		*simplex_claimed;	/* channel owning the DMA */
-	struct ata_port		*ports[0];
+	struct ata_port		*ports[];
 };
 
 struct ata_queued_cmd {