firewire: ohci: 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 <gustavoars@kernel.org>

drivers/firewire/ohci.c

@@ -111,7 +111,7 @@ struct descriptor_buffer {
 	dma_addr_t buffer_bus;
 	size_t buffer_size;
 	size_t used;
-	struct descriptor buffer[0];
+	struct descriptor buffer[];
 };
 
 struct context {