rapidio: 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>

drivers/rapidio/rio-scan.c

@@ -39,7 +39,7 @@ struct rio_id_table {
 	u16 start;	/* logical minimal id */
 	u32 max;	/* max number of IDs in table */
 	spinlock_t lock;
-	unsigned long table[0];
+	unsigned long table[];
 };
 
 static int next_destid = 0;